To be fair most men were taught that "be nice" garbage
Well here's the thing.... what church, school, after school program, extracurricular activity, aunt, uncle, mom or dad is going to tell teenage and young boys........"be dominant with that little girl".....none.
I don't mean in a sexual way, I mean in basic interactions, boys are taught to be nice to girls, because we are the physically stronger sex. There is explicit gender differences that boys and girls are taught to adhere.
SUDDENLY puberty shows up and high school and college and early 20 something appears and all that "be nice" stuff goes out the window and the socialized mantra is to be an adult with "confidence", but also a level/degree of "aggressiveness" with women you are interested in dating.
So you are talking about a literal re-socialization.... You can even argue it's like a wild animal AKA young testosterone finally able to be independent, and it takes time for some to reengineer their brains to this particular social outlook. Being nice is a double edge sword. The word has to be re-defined. This is American context, but appears in different degrees in every culture.
SUDDENLY #MeToo steps on the scene.....and just when many young men are re-engineering concepts of "niceness" and "aggressiveness" and ready to demonstrate.......#MeToo says
they are practicing rape culture, male chauvinism, etc......