Well, unfortunately, this survival rule of this world is simple and strict. It is the rule itself won't make an exception just because its victim's a little boy instead of a big tough guy, not us.
You're right, we shouldn't say this serves him right. That's just too arrogant. Like Vedderman said, it's a systemic failure that how such a young american kid chose this way to live. We can't just blame the unlucky kid or his family didn't do the right thing. But at least it is fair to say that he had it coming. Yes, with bad influences that interfered his mind, of course. But still, he is the one who made the choice.
Just because the legal system treats kids differently does not mean the reality karma won't get back to them. Human have mercy, rules don't. It's just the way it is, sadly.
Duke: I know a life of crime has led me to this sorry fate, and yet, I blame society. Society made me what I am.
Otto: That's bullshit. You're a white suburban punk just like me.
Duke: Yeah, but it still hurts.