if he had been left to roam the streets
That phrase struck me as very interesting.
I think, as children and teenagers, we were free to roam the streets and countryside; my children probably did the same from a slightly older age, meeting up with friends, going to the park etc. We, and they, played tennis on free courts, the boys played football, going scrumping was probably the worst thing we did.
We didn't go out looking for trouble. We may have seen some but avoided it although I remember seeing a group of boys throwing stones at frogs in a pond; although I was by myself I remember yelling at them to stop. They just laughed and I went home upset.,
Perhaps we were lucky but I certainly don't remember generally being fearful of gangs of knife-carrying young boys