My late wife taught in a predominately minority school where nothing which you experienced occurred. In very few schools does that occur but you are guaranteed to hear about it when it does. In some communities the school is an island of refuge from the violence and misery the kids normally live under. The students are in far greater danger going to and from school than when in it.
I went to 6 different schools in two different states. My husband went to 14 different schools in 2 different states. It’s pretty much the same everywhere. Just because teachers don’t know about it doesn’t mean it doesn’t happen. I loved learning but hated school. Most of the teens in our church want to be home schooled. They have asked me to homeschool them but legally I cannot.
The good schools are the ones that are rare not the other way around.
Also, my husband is a youth minister and he spends a good deal of time in the schools. They are out of control.