Yeah, McBride is a very corporate Democrat straight out of the Biden school, and not one of the rainbow keffiyeh lefty types in the party. Which means he might be capable of reflecting on where transactivism went off the rails - though yes, a complete inability to see women which is all too common in men who want to be women.
The American context is very different, but it's influential here at least partly because Stonewall took so many of its cues from HRC and GLAAD. I'd argue that Stonewall adopting an Americanised paradigm was a big part of how it misjudged things.
I also think about Andrew Sullivan's warning to gay activists after Obergefell not to be sore winners. Sullivan by instinct is a golden bridge man, who understood that gay marriage was a novel thing and lots of people would have to be reconciled to it. And there would be legal issues with conservative Christians working in wedding-adjacent businesses like bakers and florists. So there was Brendan Eich's ousting at Mozilla, and there's that baker in Colorado who's been dragged into court multiple times for not icing slogans on his cakes. It's as if the gay movement, who used to be great at making friends and persuading people, suddenly said, "fuck it, we've won, we get to be the bullies now." That stuff gets noticed, even by people who don't have much affinity with the targets.
So even if there was an increasingly positive attidude towards gay people, I'm not sure that transfers to the gay organisations who had achieved everything they set out to achieve, were flush with money and political clout, and decided they didn't need to do any more persuasion. So the small pivot was towards targeted punishment beatings towards people they saw as being on the wrong side of history, and the big pivot was towards trans, a very novel set of demands with a lot more impact on others (though the gay men who run the orgs aren't very good at noticing women).
This might be what McBride and Klein are getting at, though it's easier for them to blame campus revolutionaries than the big LGB orgs that became TQ+ orgs, which are still massive players in Democratic politics.
I wish someone over here would sit down with Ben Summerskill and get his take on this history.