When I was a kid, we hadn't this wrestling tradition, but still courtyard tussles had rules (no hitting someone on the ground, no ganging up on one child, not hitting someone way smaller) and if they were broken the adults quickly intervened, while they more of less left us alone if the rules were respected and we didn't do it in front of the adults.
I wonder how much of the aggravated bullying comes from the total interdiction of physical violence...