You are creating a scenario out of thin air simply to fit your belief. That is sad.
Honestly, you seem to have Mr. Zimmerman pegged as an out and out vigilante bent upon hunting down the next black person he sees on the street and outright murdering him. I'm sincerely not even trying to exaggerate. This belief of yours, which is not currently supported by any known facts, has severely tainted your judgment over this incident, IMO.
If YOU were stupid enough to start assaulting someone who was following you but not threatening you, you deserve to be shot, IMO. I've been in similar situations before, and one where a man was getting ready to draw a gun on me until I answered his question. As soon as I answered it, the situation defused and we both went on our separate ways.
Why didn't your advocate simply respond truthfully to the questions posed to him? That behavior makes me believe he was up to something. But again, I can only draw such a conclusion from the known facts, and from what we currently know, your assertions are absurd, IMO.
The cr*p about Zimmerman going after this kid because he was 'black" or that he "wore a hoody' is NONSENSE.