Jerry Seinfeld, the fantastically successful comedian, told a radio interviewer a few weeks ago that he didn't like performing his comedy at universities because, in his experience, young people no longer know how to laugh. The prevailing culture of political correctness, according to comedians like Jerry Seinfeld and Chris Rock, has turned kids into grim-faced humor police, monitoring every textbook or lecture or visiting performer for politically unacceptable forms of discourse...