Yes, this is definitely accurate I think. I've heard some gay men comment on stuff like Substack. The rise of poly etc is worrying.
What frustrates me also is that gay men like Sullivan & others are often v prominent in the media on marriage etc & it really tarnishes it if they are the image people have of it. (Let alone the effects of the behaviour they advocate). I would argue gay marriage benefited the lesbian community a lot more : though there are still issues to work on like moving in too soon & high splitting rates, most of the issues gay men experience are absent.
This is really why I have an ambivalent attitude to gay men, bc while many individuals are great obvs, it's the awkward fact that the main obstacles & things that homophobes & people w genuine concerns would critique the gay rights movement for stem from stem from uncontrolled male sexuality. NAMBLA & their toleration. Fetish behaviour at Pride marches. Rampant STDs. Open relationships. Violent & promiscuous sex. Sex w underage teens.
I sometimes think that if L/B women were the only same-sex attracted group, rights might have been slower due to women having less societal power, but many of the opposing arguments (whose concerns if not conclusions I agree w) would just not have existed. I think that can apply to other groups : it's generally not black women who participate in street crime, or Muslim women who set bombs (tho ofc women can do these things & also facilitate). This isn't to say women don't have issues, but they tend to be less overtly disruptive.
If Sullivan doesn't believe in marital fidelity etc, why didn't he just advocate for an expansion of civil partnerships to the UK model where it conferred equal benefits? It doesn't make sense how he advocated for marriage v movingly in Virtually Normal, but then doesn't seem to properly respect it. The whole point of the campaign was supposed to be, as you say, about being subject to obligations & striving for an ideal of commitment. If it's aboit being immune to criticism it misses the meaning of equality & imo is quite patronising, a bit like people acting like black people had no choice but to riot after George Floyd's murder.
As an aside., I hate the name 'civil partnership' it sounds coldly businesslike to me. An alternative name considered was 'life covenant' which sounds much more solemn & meaningful imo.