Don't overlook the inferences that can be made. Zimmerman called the police before embarking on his quest to keep Martin in sight, for example.
There's also Zimmerman's injuries, and Martin's relative lack of same.
The sound of Zimmerman's voice on the police call tells me Zimmerman was afraid of Martin.
Martin had a phone, but he didn't call anyone close enough to help him. That tells me he wasn't afraid of Zimmerman.
It's interesting that Dee Dee apparently admitted to Crump
that Martin deliberately got closer, 'trying to look in the car'. De la Rionda
managed to avoid eliciting that.
From your remark above, I take it you are inclined to believe Zimmerman threatened or used force against Martin, before Martin took a swing at Zimmerman.
Invalid inference. Incorrect conclusion.
You arrive at this point because you don't find Zimmerman credible, so when he says or implies that he did not provoke the use of force, you think that is probably a false statement.
That would be poor reasoning on my part.
Martin was more likely the aggressor if I had to guess. The evidence isn't strong enough either way for me to say I have an opinion.