Well OP, your ideological lens is making it difficult for you to understand why they're still "fighting against oppression" when they've already achieved the things they wanted originally.
The gay movement pretty much topped out in the 90s with mainstream acceptance, since that moment (actually because of that moment) they've been losing control of their own culture due to straight people "joining the cause", intersectional feminism's co-opting of their movement into trans issues and now black issues, and the genetic fault that comes with any minority activist ideology that achieves mainstream status: they don't know how to stop fighting.
See, to them, the pride movement has become diluted and lost its way. For starters, because it's now in vogue to stand up for gay people, gay clubs and pride events are being flooded by straight people who feel like just being there is fighting some sort of great cause. Imagine how enraged we get when normies flood the boards. That right there is the state of the traditionalist gays that spent their lives fighting for recognition.
Feminism started out as a sweet deal for gays, it was a solid mixture of social justice revolution style messages and the gays were able to piggyback their issues onto feminist issues. But then feminism went crazy, told them that they were being exclusive by making gay pride only about gays, and started advocating trans rights and other sexual deviancies that were a minority to the gay "majority". Now gay culture had to be accepting of the really weird shit. It was no longer about guys blowing guys, it became poly, it became orgiastic, it lost the emotional center that most men fought for. The right to simply LOVE a man.
Now, niggers. Remember how enraged the LGBT community got when BLM came along and changed the pride flag? That pissed off a lot of the old gay guard. See, any gay that's been in the community for 10+ years KNOWS that when Proposition 8 was passed in California it was because of niggers. Exit polls proved this. Now, black people are stepping in and trying to commandeer a movement they fought against from the start. But, all those new fags (who aren't really fags but rather populist assholes) are telling the old guard that flipping out over a flag is exclusionary and racist.
Which brings me to my last point; gays do the know how to stop fighting because their entire activist existence has been a fight against "oppression". Except now that they're mainstream, they have no way to stop others from invading their culture because they only know how to march, whine, and hold picket signs while engaging in attention-getting behaviour. Many of them don't realize they've already lost, and they think this is somehow the fault of the ideological right, since the right has always been "the enemy". Thus, they March and complain and yell and irritate you because they don't realize that you're not their real enemy.