And that's progress, too. But you're asking us to ignore decades of history because of one crowd at one event. That's not reasonable.
If the Republican Party wants us to believe that they're pro-LGBT now, let them prove it with legislation, not just cheers. I'll believe it once I see the majority of Republican lawmakers actively promoting full equality under the law for gay and trans people, not before.
As I've said in another comment, I would guess that being pro or anti LGBT is strongly correlated to age. Old generations were told it's bad, young generations are told it's good, and they vote accordingly -- only a few care enough to research it. It's hardly a good predictor for how good of a human being you are.
Therefore, this will naturally cease to be a problem as the old generations die out, and we're already seeing signs of it.
One would hope that we can thus move on and start discussing more interesting things (college republican/democrat debates, where you are automatically a monster if republican, I'm looking at you).
What does "equality under law" mean? Vast bodies of law supported by either democrats or republicans are discriminatory by design(for example, affirmative action, religious exemptions, etc) - you would have to define what issues need to actually be addressed, otherwise it's a fairly empty statement.
For example, gay marriage is not "equality under law", as there are still plenty of prohibitions to marriage - for example, incestuous or polygamous relationships are prohibited from marriages in many a state, which means supporting gay marriage does not support "equality under law", but extending the privilege of marriage to a wider group.
If the Republican Party wants us to believe that they're pro-LGBT now, let them prove it with legislation, not just cheers. I'll believe it once I see the majority of Republican lawmakers actively promoting full equality under the law for gay and trans people, not before.