do think when people say "we know marriage is a social construct, but it's a legal way to be able to take care of someone else and vice versa" as if those of us making a point about marriage (i would say, a lot of us being aromantic people especially) don't know this fact, are missing a bit of the point about why this is stressed and potentially not giving enough grace to (again especially aromantic) people who say this.
when it's framed as a "so just get married for legality reasons" and im like. you mean like how gay people married/marry people of the opposite gender for legality reasons? and that's considered to be a symptom of a problem, not the solution? you want people to "just" get married against their will because it's the only solution this system has available?
if people cannot or will not get married for whatever reason -- not just for being aromantic, but, say, due to inefficient disability support measures within marriage, because of having had bad experiences with marriage in the past, because of being polyamorous, because some element of marriage is ineffective, unwanted, limited, discriminatory, or hell, because you can't find somebody to marry or nobody wants to marry you, or maybe because you just plain don't want to without there being a distinct Reason -- then it's a problem that this is the only framework in place for people to be afforded certain legal and social protections.
i am glad for others that more people can get married, but it's a flawed institution with gaping holes that isn't for everyone and builds social structures that leave so many people behind and unsupported. this is abundantly obvious in the way that we saw why people pushed for the need for equal marriage in the first place.
that's what's said when making a point that it's a social construct. and also what's meant (partially) when pushing against the idea that "love" as concept isn't at the core of queer (amongst others hinted at in this post) activism, because it's about building better structures. if the only people we care about are those we "love" within a family unit, or those who successfully manage to pretend that unit without actually really wanting it, and if not being in that unit for whatever reason means that care isn't going to be/is no longer afforded, then are we really doing any better than heteronormativity?
more people need to read up on "amatonormativity" from the original source (this is a summary from the same person written in 2012 and so doesn't include aromantic, but it's all in there) before they start pushing marriage as the ultimate goal of queer liberation, or indeed any liberation.