I’m guessing a lot of abuse and neglect. And/or evangelical Christianity in the case of the people bullying her trans friend. But clearly they have had it pushed into their brains that anyone who isn’t “normal” needs to have “normal” beaten into them.
My daughter’s friend for obvious reasons. My daughter because she likes dressing like a punk rocker and they decided she’s a furry because she wears leather collars. Then we made the terrible mistake of allowing her go as the anime catgirl character she wanted to dress up as for Halloween. My wife, who is great at this stuff, made a costume that was exactly like the picture my daughter showed us. She went to school that morning and an eighth grader asked to take a picture with her… which she then put on Tiktok with some nasty messages and shared with the entire school. We didn’t even wait for the administration to make her apologize again. That was the end of her time in school.
And honestly, if I could, I’d pull her friend out of that school, pick him up every day and put him in online school with my daughter. My wife joked that I’d start a school here for queer kids (my daughter is also queer, but that wasn’t the bullying that bothered her, it was the furry stuff). Honestly, if I could, I would.