no it is certainly not an excuse but there is a difference between giving an excuse and identifying the root of the problem. I think there is a mindset in a lot of our poverty stricken areas that you get out in one of three ways: Sports, Music or Crime. You don't make it in the first two unless you are elite. There is a another way but I don't think it is always visible to theses kids.
Bornraised, this has been eating at me too so I am glad you posted. It is very sad about your nephew but if he was surrounded by positive influence and still went bad, then he is the exception not the rule. There will always be exceptions I'm afraid.