This is obviously brutish and inhumane, but it also highlights a real problem that we don't have a great solution for: what the fuck do you do about teenagers? They're often just unbearably awful. I know I was.
In the bible you get permission to declare your teenager wayward, take them outside the city gates and stone them to death.
Many Indo-European groups sent them off into the wilderness to harass and steal from distant or enemy towns, or to act as defensive scouts around your territory.
These teenagers sound like their behavior was pretty tame, but hormones are a hell of thing. Teenaged care facilities that aren't just jail or a cult should probably exist.