And see that is the kicker right there. It doesn't really matter whether Zimmerman or Martin was the initial aggressor. If it was Martin, Zimmerman always retained his self-defense immunity. However if it was Zimmerman, that say grabbed Martin, and it was Martin defending himself from an aggressor - at the point Martin was on top of Zimmerman (using the evidence presented at trial) - Zimmerman had no reasonable means of escape, at that point even if he was the aggressor he very well would have recovered his self-defense immunity.
Again I don't disagree with the verdict. What I do disagree with is those that claim they know for a fact that Martin "attacked" Zimmerman because "all the evidence says so". Well, sorry that isn't true. There is no independent evidence that corroborates Zimmerman story for that critical time between the phone call and John coming on scene. Either Zimmerman or Martin could have been the initial aggressor. We just don't know.
See that's the difference though. I'm honest enough to say (a) the verdict was correct, and (b) we don't know. Some though are invested with carrying Zimmerman's water bucket now mater what the independent evidence showed or didn't show.