Where was the threat? Where was the imminent danger?
So, a dumpy, little guy several inches shorter than Martin with a cell phone in his hand is a "threat" or a "danger?"
Unless there were witnesses or evidence to corroborate the threat or danger, it's murder.
Remember, per the evidence, Zimmerman had lost sight of Martin and was returning to his vehicle to meet the police there when the confrontation occurred. As Zimmerman was retracing his steps back to his vehicle. Are you saying that he was some kind of "speedy Gonzalez" and moved so fast that he whipped right by Martin? Or perhaps Martin was caught in some kind of time warp where he was displaced in time so that he hadn't actually moved?
Or are you saying that the witness who saw Martin on top of Zimmerman was in collusion with Zimmerman, and that Zimmerman faked his injuries, or that he knew enough to pull Martin's clothing away from his body so it would forensically support his claim that Martin was on top of him?
I am not willing to suspend disbelief or rationality to accept the "Zimmerman was guilty" delusion.