It may be the first time I largely agree with josepp.

Any reasonable person must admit that Zimmerman originated the confrontation, and that Martin was doing NOTHING illegal at the time. Once Martin had been followed and either threatened or grabbed by someone who was NOT a police officer, SYG would apply to him....Martin! It was just his bad luck that whatever he did to defend himself against Zimmerman provoked gun use! (It MAY be that Zimmerman did not display his gun until the struggle ensued! Martin may have had little warning what he was dealing with)