Beyond a shadow of a doubt, Martin was the aggressor on starting the fight. You can argue that Zimmerman provolked it by watching/following. But there is zero percent chance Zimmerman initiated the fight.
This is simply not true. What evidence do we have as regards who started the fight? (Rich, this is in response to you too.)
Here's what we KNOW:
1. Zimmerman reported Martin as suspicious, and complained that these guys "always get away."
Here's what we THINK we know:
1. Zimmerman was following Martin, and stepped out of his car to do so.
2. Martin was heading home, but refused to run home, despite the urging of Rachel.
Based on this evidence, (which admittedly is pretty slight) it is more likely that Zimmerman was the initiator. EVERYTHING else is complete conjecture, or based on Zimmerman's self-serving narrative of events.