Nick Baumann's writes about why it might be hard for Andrew Sullivan to find many people at places like the National Review who were decrying the wrongness of making laws condemning homosexuals to death or declaring slavery is wrong. However, his conclusion that these ideas were so outside the pale that for even conservatives, one would not need to say much didn't ring quite true.
When it comes to easy moral questions like enslaving people or slaughtering homosexuals, the burden of proof falls overwhelmingly on those who would buck the modern consensus.
And I thought that it wasn't that long ago one modern consensus was torture was wrong too. And it didn't take much to make it "popular" again. Nothing modern about that at all.
BTW: you really do need to read tristero's piece. He's right that the folks pushing intolerance and hate are quite influential in today's Republican Party and are the basis of much of the radicalization of the right today.