Like you say, there are only two possibilities. If one can be discounted, the other is proved.
One would have to believe that the CCW-carrying neighborhood watch captain, having given his name and location to the police, knowing the police were on their way, with a gun in his waistband, would throw the first punch against the suspcicious person he had been observing. Sorry, but that's preposterous, compared to the only other alternative.
Do you have a CCW permit? Do you carry concealed? Having done so for 25 years, I know from my experience and those related to me by others, that doing so makes one approach potential confrontation infinitely more soberly. And every class I've ever attended taught retreat first, and that physical confrontation while armed was to be avoided if at all possible. Whom you call "macho fools" in NYC are called "neighbors" down here where I live, and they don't seem to fit the liberal Yankee stereotype of the hothead with a gun. Your bias against concerned citizens like Zimmerman is obvious enough.
If you don't trust your own experience and judgment enough to pick one of the two ONLY possibilities, that's a You problem.
Were you on the Casey Anthony jury?
“Were you on the Casey Anthony jury?”
I wouldn’t go there. If anything the Casey Anthony defense should be a model for Zimmerman. The state in that case couldn’t prove its case, merely relying on what was not a crime—i.e. failing to report the kid’s disappearance—to hint that she was the one who killed her. Well, Casey shutting her mouth for a month was far worse than Zimmerman “following” and “confronting” Martin and getting out of his truck. Someone killed Caylee, and I wouldn’t be surprised if it was Casey.
But you can’t convict according to the “someone did it” mindset, nor by the “Martin was unarmed” mindset. Neither adds up to conviction. There was some evidence against Casey, in the form of internet searches, sticker residue, and trunk smells. Nothing to surpass the reasonable doubt bar, as the defense could reasonably posit that she drowned in the pool and Casey’s dad helped her cover it up. Likewise, Zimmerman could have started the fight and resorted to shooting once he was losing. But it also could’ve happened like I think it probably did, i.e. by Martin committing assault by attacking Zimmerman and Zimmerman shooting Martin.