With all due respect, they never really changed their minds. Their minds were set and in favor of this from the beginning of their political careers. However, it is very difficult to win a general, national election when you take a stand that a majority of Americans oppose, so you say that you are against the controversial action to side with the majority and prevent political casualties. And that is what happened.
Notice the timing of this “evolution.” Obama “evolved” when it was politically convenient for him to do so, when the issue no longer served as a real political liability for him. But after a while, nobody seemed to care (particularly the 3+ million Conservatives who obviously weren’t motivated enough about this issue to go to the polls in 2012), so ever since then, it has become widely perceived as a “non-issue” and as such, has even permitted the environment for many Republicans (whether gay or straight and sympathetic) to support gay marriage. So, I am not surprised in the slightest.
you’re right