While I didn't go to more wealthy schools as a child, I grew up in a 'middle class to poorish' rural area in the midwest and moved to a poorish area in the south.

I'll use your own words to describe the change in the experience

>I was just trying to survive a situation that was both psychologically and physically abusive, with public humiliation rituals, solitary confinement, and gangs of bullies that cornered and robbed people and violently punished social non conformity-

I got the full 'the science teacher is the bully coach and believes the world was created 6000 years ago, and if you were one of the kids they liked you could commit crimes, and you were not liked then crimes could be committed against you' experience.