As a high school teacher for 35 years, I saw a number of mean girls—and mean boys, as well. Bullies is what we called them, although people don’t think of that term for girls. But it’s exactly the same thing, with more of an emphasis on emotional, rather than physical, battering.
Yes, I agree it’s usually—maybe always—caused by a home situation. And yes, I agree that counseling can help. But the other thing that schools can do is try to turn these bullies into avid readers.
I never had an avid reader that was a bully. Because books have narrators, a reader can see the effect of bullying and trauma on a victim. In movies and video games we are outside of the victims. In books, we are inside. Most books—certainly the kind of juvenile and popular fiction that school kids read—engender sympathy.
There are all kinds of academic reason to make developing avid readers a priority, but there is this social one as well.