I don't think it started with Trump. As hard as it may be to believe, the political ball got rolling back in Reagan's day when he helped defeat Proposition 6 in California. I don't know a lot about the bill other than it made it legal to fire teachers who were known homosexuals (or who publicly supported homosexuality), but Reagan was against it.
Interesting that most conservative republicans with gay children, like Reagan, have not supported the party's position on gay rights. Dick Cheney, for example, favored equal rights for gays. It's hard to hate a group if your child is among them.
Out of that came the Log Cabin Republicans (so-called because they champion liberty and equality as they read it in Abraham Lincoln). They have been around since then - and increasingly active. So I don't think Trump is leading the way in gaining homosexual acceptance in the GOP.
Trump seems to be the exception. I don't think any of his offspring are gay.
Having said that, I see the political reality simply a reflection of the cultural reality. The problem isn't in politics but it is certainly seen in living color in DC. Obama's leftist approach made use of the question of where real power lie - in a title or in numbers. And I think he knew there had been a distinctively left leaning move for years. One I would say is typically indicative of a loosening of public morality. The left wants a loosening of public morality, the libertarian wants a purely private definition of public morality and the right wants a strongly defined (Christian) public morality.
Most libertarians would reject the notion of "public morality", seeing morality as a purely private issue, unless it involved abusing the freedom of others.