Worrying. It seems to me that it depends on where their final loyalties are: to their gangs, or to their new country and their fellow soldiers.
There is a tradition of taking juvenile delinquents or some kinds of criminals into the military and making men of them, at least there used to be. The Foreign Legion was most famous for that, but the US Military has done it, at least in the past.
What the present situation is, I have no idea.
You are correct: this guy was destined to be a punk before a judge sent him on a date with the Marine Corps:
http://en.wikipedia.org/wiki/R._Lee_Ermey