I have a different theory. Pieties of any sort make easy butts of crude jokes (cf. the recent New Yorker piece on Michael Moore), and making crude jokes and outrageous statements have been in fashion lately. It is a part of being "popular" nowadays - manifested by the adoption of anything shocking and attention grabbing, from the gutter language, to Nazi symbols, to crude jokes and blatantly "irreverent" attitudes. A respectable private school teacher would not probably go as far as dressing like a punk or talking like a rapper, but crude jokes and irreverence toward pieties, especially liberal ones, fits well the requirements to be "popular."
In short is a reflexive faux-populism-cum-shock-effect post-modern style, not a consciously adopted (even if vile) ideology.
Wojtek