Well, perhaps they really don’t.
Notice this picture is on the left.
At some point between the 1950s and 1960s (1:13AM on Tuesday, July 12, 1963, to be exact), the idea of the “egghead” academic developed into the “commmie-red pothead” character. A brief article from the Washington Post indicates that the real state of academia challenges the facile caricature of university and college teachers.
RJB (Solidarity, comrades!)
Skeptical Humanities 
THe Marxist-Leninist Politically Correct conspiracy has been a meme of parts of the Right for more than a generation. Its amazing the hysterical reaction you get from many when you question the meme. In my opinion it deserves to be analyzed as an example of political paranoia along with such conspiracy phobia as the Edlers of Zion, Truthers and Birthers. Oh David Horowitz is mentioned in the article. Lets just say Mary McCarthy said about Lillian Hellman applies to paraphrase “Everything that comes out of his mouth is a lie including ‘a’ and ‘and’.