At a recent panel discussion that I attended, Historian Heather Cox Richardson summed it succinctly:
We elected a president who rates women by the size of their breasts, who called bragging about how he has grabbed women's private parts without asking permission - which is sexual assault - as just "locker room talk."
We elected a man who went on the Howard Stern show bragging about how he liked to barge into the ladies dressing room uninvited and see his pageant girls naked (bragging he got away with it because he was president of the show).
We elected a man who bragged about the size of his own daughter's breast and said that if she wasn't his daughter, he'd probably be dating her, and said that his daughter is hot enough to pose in Playboy.
We elected a man who said he'd love to have sex with Lindsey Lohan because "deeply troubled" girls are the best in bed, who called his own wife a "young, beautiful piece of ass", who mocked a woman saying she had "blood coming out of her wherever."
These are but a few of the countless misogynistic things Trump has said and done.
If you think that making someone like this the president of the USA doesn't shape the self-view of young girls, doesn't normalize sexism, and doesn't need women to stand up for their worth, then you're on the wrong side of history.
Not only that, but plenty of men attended these marches too; men who are fathers, brothers, husbands and friends of amazing women and who wanted to publicly demonstrate that they're in opposition to such dreadfully sexist misogyny.