In my opinion, people should prioritize romantic relationships when they start because those are two (or more) people getting into a new dynamic and figuring out how that works for them, or getting to know each other to see if they'll work out as romantic partners. It depends on how they wanna handle it though, so I think that's subjective (...and honestly, I think that could apply to other relationships too. If I made a new friend and could hang out with them or someone I've been friends with for years, I'd probably choose the new person, unless I hadn't seen the other for a while/they need my help/we'd already made plans, etc.)
Otherwise... Yeah, I don't really see the point in putting a romantic partner above all else. I guess you should, if you upset them or are going through a rough patch with them, but that applies to any relationship. Same with if you haven't spent much time with them recently or if they depend on you for whatever reason.
I think the idea that romance should be prioritized comes from the fact that it is often... mysticized? Idealized? Romanticized even (I can use that word as a synonym and that speaks volumes). People mention their "soulmate", their "other half", the "love of their life", their "one and only", their "special someone" and sometimes even "the one". Sure, it's often dramatized too, but the sentiments are genuine.
(...okay, I'm going off on a tangent here. I have a problem with pretty much all of these terms. "Soulmate", I actually don't have much beef with. I think it's just two people who are similar or "cut from the same cloth" and click together. Shame it's usually only used for romance though. "Other half" implies people are incomplete without a romantic relationship. That's just plain sad... "Love of their life" is nice, but very extreme. Usually, they're the love of a certain period of their life and then they leave it. "One and only" is... weird. I guess it works for monogamous relationships, because they're their "one and only lover", but that leaves out poly romance. "Special someone" is dumb. What makes a romantic partner more special? And "the one" just seems unhealthy. Both of aros and allos who get told that one day they'll "find the one". All of the terms devalue non-romantic relationships and make it seem like romance is the end-all-be-all).
There is an incredible amount of love songs. There is romance in films and books, and sometimes that's the whole point of the story - Romance is also a genre! The term "heartbreak" is most used to refer to the end of a romantic relationship. I could go on, but honestly there's no reason to, because aros already know all of this, and I'm pretty sure any allos in this blog would know too.
Point is, when romance is hailed as this amazing-great-fantastic-awesome thing that all people should have, then there's:
Pressure to be and stay in a romantic relationship, which may lead to prioritizing it over everything else, so you don't "die alone" (Smaller tagent 2: Electric Boogaloo, if you live with anyone, then you probably won't die alone. Why would it have to be a lover? Any good friend would probably visit their friend's deathbed too. And it's not like a romantic partner will teleport to your side if you're run over by a car and die there) or are labeled as a lonely loser ("Virgin" as an insult comes to mind, since romance often involves sex).
People buying into the idea that romance is the goal in life and that everything else is secondary. To a less extreme extent than that, but still making it a priority.
That concludes my loooonnngg spiel. Thanks for reading. Remember Better Than Sex cake exists. Okay, bye.
You know what? On the first part, fair enough, as someone who can't feel romantic attraction I still personally don't see it but I can at the very least understand the logic for sure.
On all of the rest β couldn't have said it better myself, thank you so much. The system IS kinda fucked.