If someone should happen to follow Zimmerman around with a gun, provoke him, chase him, and otherwise harass him until he retaliates, they now have legal precedent to kill him in self-defense, right? You can't prove any racial reasoning.
Yeah, self-defense is what you call it when a guy four inches taller in on top of you, beating you to death. What about John White, who walked out of his securely locked house to confront a bunch of kids making noise, even though he knew the cops were on their way? Not one kid laid a finger on him, but when he shot and killed one, he was only faced with gun charges, and pardoned of those charges as soon as his state got a governor the same race as he. The difference was, John White was black and, in a highly typical case of interracial homicide, shot a white child, so there was no racial outcry. President Bush did not point out that if he had a son, he'd look like John White's victim (and if Barack Obama had another daughter, she'd look a lot like that Jenteal idiot; she'd certainly be just as racist, given her father's propensity for interjecting himself into local scuffles on the side of the black man and her mother's thesis topic at Princeton), and every one seemed to be pretty much on the side of the homeowner getting harassed by punks. Even though said homeowner had no need to take a gun and leave his house to confront the kids.
As for the stupidity of Zimmerman, he WAS a neighborhood watch guy. There HAD been a rash of crimes in the neighborhood by black perpetrators (of which Zimmerman had been one of the victims), and at least one had been caught by concerned citizens tailing him. If Trayvon Martin had a right to be walking where he was, so did Zimmerman, who LIVED there. We don't know what happened in their confrontation, but unless you are going to presume some sort of insane scenario where Zimmerman was baiting Martin into attacking him so he could shoot, there is no logical or reasonable way you can justify Martin doing something to cause wounds to the back of Zimmerman's head.