Rebelling against the perceived establishment as presented to them by their teachers (some of whom are that old) probably had something to do with it. (Their parents too, but their parents aren't >60)

Young men particularly have been getting dosed with idpol messaging about men by their predominantly female teachers from a young age. Anecdotally, there's also a general thing where the older a teacher gets the more embittered by experience they become, and they become more likely to fall into negative behavior patterns like having "nemesis students" they like to pick on, or exhibiting flagrant bias in the classroom against an entire gender.