The reply above me mostly covers it, but there is another layer to my frustration here, which I don't think I was able to convey in the original post. So here's a more direct attempt at it.
First of all on the question of what is "good" or "bad" in terms of fiction. I don't think it's useful to categorize any fiction as "bad", or to say it's "bad" to read or write fiction that reiterates harmful/reductive worldviews. Fiction doesn't invent these ways of thinking, and while it is part of the cycle of reaffirming and consolidating views, it's only a very small corner of that much larger social process. Trying to control, prevent, or even morally judge fiction for its role in this process leads to many immediate types of harm (censorship, moral panics) and also doesn't even begin to touch the actual process of worldview transmission.
Also, fiction often serves to make legible what those types of underlying biases and narratives are, and what draws people to emotionally relate to them. Discussing and critiquing trends that appear in fiction is a way to learn about and unpack social biases, including fairly nuanced and complex ones that might be hard to pin down in other terms. That type of discussion is the context in which the original post was written: a discussion of narrative trends that often appear in stories that bill themselves as "queernorm", and how those trends frequently reinforce regressive views on monogamy, amatonormativity, marriage, gender segregation, and even reproductive control of women.
Not to say that any of those are at all intrinsic to writing a fictional world in which being queer is not socially punished! Just observing that over and over, in stories which center a romantic arc between (usually cismale) gay leads, the specific narrative choices that are made to uplift the social valuing of that relationship, imply pretty awful things about what may be happening to other people offpage. And the reason those choices get made in those ways, is because the narrative is aiming to provide the emotional satisfaction of seeing a queer relationship get emotionally valued *in the same ways* we are used to seeing straight relationships valued in fiction. Which is interesting, because the ways straight relationships are valued in fiction far overshoot "this is an accepted aspect of your life", running more towards propaganda on the all-consuming life-affirming value of getting married and having children, for women in particular. Trying to transpose that entire narrative emotional arc onto a couple of cis guys lands you in some tricky places. And even in the case of queernorm stories that don't go all-out heavy handed with this, there are very often weird echoes of this approach.
For example: a big part of romance narrative propaganda is about laundering "bearing children within a marriage is an absolute necessity to have a stable future, someone to inherit your livelihood, and care for you in your old age; and also if you're a woman you have a lot riding on being able to bear a child yourself because otherwise your husband will probably take another wife or mistress in order to secure offspring, leaving you in a pretty rough place" into a lot of emotional heart-string-pulling about the irreplaceable emotional experience of having *your own child together* as a romantic relationship goal. When queernorm stories try to provide this emotional beat to a queer couple, this focus on the romantic couple having *sole parental ownership* of the child generally remains, often explicitly cutting ties to any other family or community the kid might have come from. If you know even a little bit about the history and present of adoption as a concept, this casts some incredibly bleak narrative shadows.
(There was a whole rabbithole of discussion about this I'm not going to rehash but in brief: no, random orphans are not the easy answer you think they are. Please go read about how the christian adoption industry has shaped the modern concept of adoption before you even try to talk about fictional adoption to me. Please. And double that for surrogacy! Holy shit!)
((Notably, while stories in which a cis male couple Aquires A Child tend to brush past or completely diregard the kid's biological parents, stories in which a cis female couple decide to have a kid by one of them getting pregnant often focus inordinately on the thoughtful selection of a biological father. Folks, we are not beating the patriarchy allegations here....))
Anyway! Setting all that sort of detail aside: stories keep leaning into these narrative tropes and emotional beats because they resonate in some way with the author and/or audience. Often that resonance is because of how they relate to other stories: straight romance tropes are so well-worn that just seeing them invoked in a queer context can create an emotional resonance, regardless of how much troubling implication has been shoved in to bend the trope into shape. And romance, as a genre and a readership, has a particularly complicated relationship with the implications left behind by its emotional beats. Because there are so many types of overt social propaganda around romance, and so many systems of oppression tangled up in it, romance fiction is pretty much constantly dealing with baggage and implications. And for readers, the baseline approach to that minefield is to engage with what you find emotionally interesting, and not put too much moral weight on anything, because damn it's a mess in there. And sometimes, as I mentioned before, to go trawling through the trends and implications, to see what they say about broader social perspectives.
And in this case, what I think the trend of applying straight romance tropes to queer relationship stories says about the bigger social picture, is that there is a cohort of people who consider their queer identity to be an isolated, self-contained identity trait, rather than being located within a continuum of social pressures around gender, relationships, childbearing, financial and social inheritance, etc. In order to look at a queernorm story in which for example, a prince marries a man and this is acknowledged as a marriage and everyone is happy about it - and perceive that as being a queer story - you have to have a definition of queerness based entirely around an internal experience of gender and attraction. Rather than defining queerness as a disjunction between the way you want to live your life, and the social pressures that punish or coerce you into having a certain social role and type of relationship.
In fact, trying to define what "queer" even means in the context of a queernorm setting very quickly becomes a mess of circular reasoning, because the definitions of "gender" and "attraction" and "relationship" and "marriage" being used, are all forms defined in the current sociocultural context, in which they are explicitly shaped if not outright defined by cisheteronormativity. What are these marriage concepts even doing in this setting? Why hasn't the social position of women changed? The only way in which these stories make any sense is from the lens of our society, from which we paint in the sexist and homophobic context everywhere it's necessary to make the society as described hang together, and then scrub it away from the narrow view window of the lead couple.
Now to be clear: there's tons of fiction out there that shakes up heterosexual relationship norms in all sorts of ways. Many times this ends up looking like a society in which relationships our society treats as queer are accepted readily! Arguably, you could call this all queernorm, and then half of what I'm saying wouldn't make any sense.
But that isn't the subsection of fiction I'm talking about, and I don't think it's what you're asking about either, because of this specific bit of phrasing:
"queerness is no longer hated or thought of as 'less than', but instead is just as 'normal' as being cishet is."
Just as normal! Which means we are explicitly talking about a world where being cishet is still normal. Where the concept of a normal, acceptable, socially supported type of relationship exists, which means there are still social pressures built around romantic life partnerships. And the concepts of cis/trans male/female still exist basically just like in our society, because that is the framework in which we are defining "straight" or "gay", they've just been somehow severed from the social forces that relate the definition of genders to the construction of cisheteropatriarchy.
And there is a lot of fiction out there that operates on these terms! Actually a surprisingly abundant amount! And it all operates on this sort of cognitive dissonance basis, in which the sexism that holds the whole society together is present everywhere except when you're looking directly at it.
And that also is not really unusual as far as the romance genre goes. Romance is written to hit certain emotional beats and to avoid hitting other ones, most of those emotions are derived from factors that in reality have a lot of complicated baggage, so a lot of that baggage is often getting handwaved and shoved out of sight so you don't emotionally step in it.
And as I said up top I think that's fundamentally not a moral issue. Playing around with narratives and emotional constructs and tropes and socially normalized assumptions - it's fun, it's interesting, some of it pisses you off more badly than you can possibly articulate, but it's all a reflection of what runs through society. Saying that certain ways stories handle these things frustrate or upset me or alienate me isn't saying that those stories are bad. Nor is it saying that people who like those stories are bad, just that I disagree with them.
BUT. When you challenge stories that treat queerness as "just as normal", when you pick apart the worldbuilding and find tons of hidden sexism, when you just generally complain that this sort of thing is frustrating and exhausting, it turns out that you get a lot of pushback from people who think queernorm-type stories are actively morally good. That they constitute some type of meaningful social progress towards queer rights and openmindedness. And this is what I take issue with.
I do believe it's possible for fiction to have a direct, positive effect on people's social conscience. I think that sometimes people read stories that introduce them to new ways of thinking, that challenge and overturn their unexamined biases. I don't think this happens with any predictability or regularity, it has a lot to do with the specific landscape of where that person is at in their understanding of the world, more so even than it has to do with how the book is written. I think attempts to write books with the aim of inducing this effect are probably less effective at actually achieving it than writing books that come sincerely from what the author finds compelling. (And also probably more boring.)
But I don't think a story that reaffirms the idealization of regressive romantic tropes, just for the sake of projecting them onto a couple the reader's society treats as queer, is going to cause that sort of expansion of social values. I just do not think it is structurally in the cards. If the major emotional punch of a story relies on upholding normative relationship values (but gay) then normative relationship values is what's going to land.
And fundamentally, I think this is a problem because I think that the derision of queer relationships is only another face of the same social force as the pressure to be in a correct, cis-hetero reproductive marriage. A socially correct marriage ensures the proliferation of gender roles, the gendered division of labor, reproductive control of women, social control over children, and in general the production of a new generation of children who are correctly encultured to uphold these same values, and to take care of you in your old age. It's all in there. All relationship values tie back to this conglomerate goal: chastity, monogamy and faithfulness, lifelong stability of partnerships, financial provision for the family, emotional labor and childcare, hyper-gendered behavior in flirting, on and on. And to be queer is to be defined as being a threat to this structure. By being someone who doesn't fit one of the allowed roles, by refusing the role you're assigned, by wanting to structure your life in some other way and acting on it.
Social movements have pried loose certain pieces of the trap - no-fault divorce, birth control and abortion, education for women and the right for women to to hold their own jobs and open their own bank accounts. It is much less inescapable than it once was, which has led some people to act like it's truly become optional. However the social pressures to conformity with at least the general shape of a heteronormative relationship are still extremely strong.
So, to position queer relationships as being in alignment with core cultural relationship values is sort of a tricky thing. From one angle, it looks like uplifting queer relationships towards the social status given to straight relationships, allowing people to prioritize their partners openly without strife. From another angle, it looks like a concession, cutting off the scope and variety of ways queer people live and love, to redefine a slice of them as "acceptable enough" to allow some people back into the social fold. And from yet another angle, it looks like political display of submission to the institution of marriage and its ideals: look, we're not challenging your way of life, we're not dismantling the patriarchy and the gender binary and the way you live and love and raise children, we're playing along! Just like you, but over here, not a threat to your social control over your children!
I'm not casting personal judgment on people who position their personal lives this way to get by: it's hard to be living in this society, we all do what we do. And I'm certainly not casting moral judgment on people for what dynamics they enjoy in fiction, what kind of wish fulfillment scratches what emotional itch. It's absurd to treat that sort of thing as political in any serious sense.
Unless you make it your politics. If you are out here saying that you actively support normalizing queer relationships as being Just Like straight relationships, equally normal and subject to just the same social values - if you think fiction pushing this perspective is a force of political good - then my political opinion is that that's a copout and a deflection from actually pushing for social changes that would help people live free of gendered and sexual oppression, including discrimination for being queer.
And my nonpolitical opinion remains that there is fiction out there doing more interesting things with queerness and I prefer it.
