In this case, not much. Did you do a dictionary check to make sure you have a handle on the word? It's one of those ones we all think we know 100%, but really we just know broad strokes.
Dehumanize (from Google): transitive verb. : to deprive (someone or something) of human qualities, personality, or dignity: such as. : to subject (someone, such as a prisoner) to inhuman or degrading conditions or treatment.
Men define themselves by being NOT feminine. To do so, they other and denigrate the feminine. They place themselves above ; believe themselves to be superior. They come to hate the feminine within themselves and seek to root it out. It's a natural extension of that process that they would come to hate women as well. How could they not, when women are the living embodiment of the feminine (whether they want it or not).
Men live in a state of cognitive dissonance as to how much they hate the feminine and women because they also desire it, long for it, and are sexually stimulated by it (generally speaking).
Virginity is prized in our culture so teenage girls get blowback from all sides. Her male peers who are jealous, upping The Game of competition and will use girls to score points, and are leaning to objectify their former friends for sex. Her mother and female role models in a warped effort to keep her safe from men will curtal her freesom and start to criticize her harshly about every.goddamned.little.thing; she feels censured, scrutinized, and like nothing she does is ever right. Then there's the older men. Do we really need to go there? They're losing their youth and will grasp at young women for attention in order to not feel old. They'll use her in whatever way they can get away with to feel relevant again. You're gonna dodge a lot of creeps as a teenage girl. With the advent of the internet, they are literally crawling out of the woodwork. Most men willfully blind themselves to how big a problem this is. Churches preach to young girls that their bodies are wrong, evil and that men are not responsible for their behavior. You are responsible for.managing their lust. At the same time, because of virginity culture, these girls are kept as ignorant as possible about sex and the dangers they face. (It would hurt men's feelings if they were regarded with an appropriate amount of suspicion given the current climate.)
The result is that young girls hit this age where they're regarded as fully sexual beings ripe for the plucking before they even have a full understanding of what sex is and society treats them like they are natural experts.
It's insane.
And you think that's NOT dehumanizing? Really? Go read that definition again. Do you not see how girls being objectified deprived them of personhood and dignity?