Yes, we've come around to accept gay people after a long and public social debate where it's essentially been determined there's no good reason not to. Which is undoubtedly an excellent thing. With these things, however, it seems like they've trailed along unnoticed and that it is now mandatory that we not question anyone's right to "determine their own identity" without having ever really established why. So when talking to people, reading articles, and even, say The New York Times comment section, there's an overwhelming sense of bemusement as to "since when exactly did we decide this sort of thing was now normal?"
The difference being, that for gays we didn't 'determine our own identity'; we already had it (in that we loved other people of our gender) We were just banned from expressing it. The same is broadly true of women; women were only ever allowed to be what men determined women should be, but they were always women.