Maybe its a US thing? Grew up in the Soviet Block Countries, and fighting was very looked down on.
I did encounter some, but it was more like we as kids watched a lot of US media and thought this was how we needed to behave but were more “playing at it” than actually being vindictive.
My one fight in school was with the “toughest” kid in my age group (I was the nerdy outsider they were bonding over to defeat), we duked it out in the yard with half of the school watching, and didn’t get a clear winner. We both got tired and called it quits.
Both got reprimanded of course. Weirdly enough that was the most violence I’ve encountered in my life, period.
I blame video games. Aggressive teens got an outlet where they can establish rankings, troll, be dicks, or defend others, with zero parent supervision.
In my case, since it was done in computer cafes, it had its strong social aspect, with crowds cheering, gangs and clans. Counter Strike was more of a religion to us than anything. And it was so much fun that we didn’t really need “the real thing”.