Just the fact that they would have got their backsides tanned was part of it. They had the opportunity to experience and endure pain and learn how to handle it and to show they could handle it.
Other opportunities came in the most common sporting games, in wrestling and fighting with each other. Kids didn’t wear helmets when they rode bikes, or kneepads on skateboards. You got hurt sometimes. Don’t get me wrong - there are good reasons for a lot of the changes (I’d never let my kids ride a bike without a helmet).
I teach high school boys - the boys of today aren’t allowed to do one fourth of what we used to do when I was at school. They get hurt a lot less, and that’s not a bad thing, except boys are hardwired to show off their physical toughness and to compete with each other physically. As we give them less options to do this, they make up their own.
Personally I wouldn’t link it to gangs - that might be about seeking certain other things a lot of boys miss out on (cameraderie etc) but it’s not the same thing as this.
Boys want danger and physical challenges. Adults should do their best to make sure they have these as safely as possible, or they will make up their own.
Well put.