>Pinker traces the origins of this dynamic all the way back to 1975 and the publication of E.O. Wilson’s “Sociobiology,” when Wilson and other biologists “would get shouted down” for expressing the view that genetic and other evolutionary considerations determine, in part, social organization.

Two things that might serve as food for thought:

1) I guarantee that know-it-all, newly-minted young adults getting mad at professors didn't start in 1975, though simultaneous social shifts (e.g. things like the anti-Vietnam-War movement) might have made it more socially acceptable for the youngins to speak up in those places.

2) People complaining about being oppressed on campus because of their ideas frequently seem to have the same weird idea. Whereas, no one goes and yells at Lee Smolin when he bags on string theory.