This is really sad and disturbing. Mine was one of the last cohorts of students to go to university before the internet/social media really took off (was there late '90s/early'00s) and, while there was some degree of misogynistic behaviour back then, it was mostly confined to drunken banter on 'Sports Night' or specific, niche clubs and societies - sexism was seldom overt, and on the rare occasions it became so it was quickly clamped down on by the SU. Now, though, it seems to have become part of mainstream university culture. 
I work as a teacher now, and it has struck me numerous times how much more delineated along gender lines children have become over the past decade or so - the whole overt gender conditioning thing seems to be a fairly recent, but very stark trend. Not sure where it stems from, or why now, but I find it scary that so many parents are merrily playing along with it without analysing the future implications for their children.
Agree that it has little to do with class, though - I was at a Russell Group university that's somewhat infamous for its 'Rah' element, and the students there were as capable of extremes of behaviour as anyone else. In fact, I agree with SardineQueen and others in that ime male students from middle class, privileged, 'establishment' backgrounds are more likely to display sexist attitudes than those who have had a more alternative/less mainstream upbringing and education.