Maybe I'll get downvoted for this but I gotta say it. I'm a woman, for the record.

All of the bullying and harassment that I endured in school came from other girls. All of it. They called me every name under the sun. They told me to go kill myself because I was "hideous" and I was told repeatedly that no one would ever love me and no one wanted to be my friend. They shoved me, stole/broke my stuff, spat on me, forced me to eat sand from the sandbox, banged my head on the bathroom wall, spread lies about me. The older I got, the worse it was, and when I was around 13 and finally had a real friend, who happened to be a boy, I became a "slut" too, and they spread rumors about me and him. We actually changed schools together, after begging our parents for weeks, because he was getting harassed by the girls too.

It didn't change when I grew older, it just became more discreet. Adults (usually) know better than to behave like that at work. I couldn't count how many female friends I've distanced myself from over the years because they called other women sluts though. I couldn't count how many have judged and mocked other women behind their back over their appearance or number of sexual partners. It's just that they don't do it to your face anymore when they're adults.

We all grow up in the same society, with the same values, being exposed to the same things. So when you're a girl, you learn pretty early that your worth as a human being is determined by your physical appearance. Later on, you add number of sexual partners to that list. And it's not surprising that a huge number of women believe this stuff and spew as much hate and venom as men. I wouldn't be surprised if more women did this sort of thing than men. It's internalized sexism. It exists. Is it because men created these ideas in the first place, though? Yes. Religion is largely to blame for this, and religion was (still is) dominated by men. Men have been in power for a very long time, and there's nothing more misogynistic than a deeply religious man. So yeah, blame the patriarchy. Women are victims of it even when they don't realize it, and then they go on to victimize each other.