BBM
Following someone is not aggressive? I disagree. It might not be illegal, though I suspect following a child is in many places, but it is without a doubt both aggressive and threatening. I bet you would be frightened if someone was simply following you in your car, I know I would, let alone having some creepy dude driving and then running after you at night in the rain. In all honesty, I am a guy who's been in more fights than Zimmerman has years, and even so that would scare the heeby jeebies out of me. I'd figure the next BTK was after me. I cannot imagine how freaked out I would have been as a kid.
The person in this case who had every reason to be afraid was TM. He was the one being followed, he was the one alone in the rain, unarmed. Zimmerman was the guy with the car and gun following him.
What Zimmerman's defenders seem to want to claim is that he had the right to pursue anyone he liked (which he did), scare the hell out of them (which he did), ignore police instructions to stop (which he did), and if his prey became frightened enough to defend themselves (which might have happened), Zimmerman could then legally kick their butts (if he could) or kill them (if he failed)...
And either way call it self defense. It's ridiculous in my opinion.
If TM waited in ambush and brained Zimmerman with a brick as he went slinking past, Trayvon would be correctly able to claim self defense. He RAN and the guy kept following him, he hid and the guy tried to hunt him down.