Here's the story as I understand it:
Zimmerman, a Neighborhood Watch member after a recent string of burglaries in his neighborhood, sees a young male he doesn't recognize. Young males are overwhelmingly the perpetrators of property crimes, regardless of race. Doing his volunteer job, he follows the suspicious person and calls 911.NOTHING prior to that next to last paragraph has any standing on the defensive shooting. Once the assault began, Zimmerman was justified in defending himself.
Martin, fresh to the neighborhood because of personal problem - he's staying with his father and his father's fiance - notices that he's being followed by a "creepy-ass cracker."
Zimmerman is advised by the 911 operator that he "doesn't need" to follow Martin. The police are on their way, but Zimmerman gets out of his truck and follows anyway. He's Neighborhood Watch, remember? He loses sight of Martin.
Returning to his truck, he is confronted by Martin, who is younger, fitter, and probably stronger. The confrontation is violent. Zimmerman ends up on his back under Martin, getting beaten. His nose is broken and his head shows signs of trauma indicating that it was in contact with concrete.
In fear for his life or at least serious injury, Zimmerman draws his properly licensed concealed weapon and fires one shot, stopping the assault.
I'm glad the jury understood that.
Now we get to see what happens with the racial grievance crowd.