The Thought Police

I was watching Bill Maher on CNN for a few minutes last night. He started off OK, denouncing political correctness as valuing feelings over the truth. He really got off track however when he attributed PC to the right wing evangelical. Does Bill not know that PC is a invention of the left?
Take the Larry Summers' fiasco as an example (this seems appropriate, since this was the issue that prompted the question) . President Summers suggested the completely obvious idea that men and women are different, and that perhaps this difference is why there are more men in the hard science disciplines. For this thought, Summers has been relentlessly attacked, not by Evangelical Christians per se, but by Ivy League intellectuals, i.e. THE LEFT. Of course that innate differences are what account for more men in the sciences is completely possible, but this thought would contradict the Radical Feminist article of faith that women as a whole can do anything men as a whole can do, and can do whatever activity is in question at least as well as men do it. I suppose that may be, and feminists are welcome to make that argument. But why are people like Larry Summers, a liberal, not allowed to hypothesize otherwise, especially when the facts lead him to an alternative conclusion?
Apparently some thoughts are just off limits. Lucky for us we have the liberal though police to tell us just which thoughts are acceptable and which aren't allowed. What evangelical have to do with this, I still have no idea.