Why hate men?

I think, for most, even they may not realize it, it's to break the pattern of emotional ambivalence toward men. It's making the choice that frees them from the cognitive dissonance that being sexually attracted to someone who hates you causes.

Men may choose that head space of cognitive dissonance but it's thrust upon women.

Most women don't want to be men because they don't want to be in that head space and they don't want to be in a position of liking it, again, because for men it's a choice.