I will say, I do know GOOD parents that have done their BEST to raise a good child, to have that child go wrong.
Sometimes you just can't change things.
So IMHO you are spot on , save for the responsibility was on Trayvon's shoulders alone. ASSUMING the parents did all they could, and thats not a given.
Just saying this for those out there that have done all they can, and still have kids go wrong at times.
Jeff