In the school where I teach racism is seen as disgusting, sexism overtly unacceptable, but OK as a joke (don't you women have a sense of humour?), homophobia as rational, and gender stereotypes more or less invisible except to one or two radical feminist harridans. (Including yours truly I'm proud to say.)

Teenage boys in my experience are desperate to conform to stereotypes and what they perceive as the norm, far more than girls of their age. So this crap, offered to them as a norm, is doubly pernicious.