Because heavens knows, we can’t possibly make parents bring their children up with decent values, respect etc etc..
The attitudes are learnt at home, reinforced in school mixing with peers. Where else can we get in and try to stop the rot?
Boys and sexual harassment, girls ganging up on other girls, racism, homophobia, islamophobia - kids absorb parental views, this isn’t something new. Don’t blame ‘the boys’ - blame society, blame their parents. Then come up with a zero cost, human rights foolproof way to eradicate such views across all of society.
Or you could just try getting the right info in robustly, via schools where we at least have them captive for a few hours, and some minds might be changed.
Or just keep ‘blaming boys’ with no realistic solution.