The reason the student protests of the 1960s didn't lead to political correctness was precisely that — they were student movements. They didn't have any real power.
I don't know what Graham thinks 'political correctness' would have looked like in the 1960s – most Americans still thought women's lib was a joke, many Americans were fighting to preserve segregation, and nobody had heard of such a thing as a gay rights movement.Ernst Röhm, leader of the Nazi's SA forces, was gay. People did not join the Nazi movement because of the impeccable life style of their leaders, but their political program. Same with AfD or Trumpists.
It's reasonably simple: Be sufficiently powerful and your sins will be overlooked (for a recent example: See Donald Trump's "sentence" in New York). And in non-rule-of-law societies your sins-while-powerful will be used against you (this is why democracies historically always had immunity arrangements)