How are Zimmerman's complete and utter failure to get his story straight and the 911 transcript where he was told to cease his pursuit, but refused to do so out of his notion that Martin was a burglar that would 'get away' not details of the case? That's what I was basing my judgement on.
You don't hunt people down in self defense. What of Martin's right to defend himself against someone who cornered him with the intention of starting a confrontation? Where do you get the idea he attacked first rather than after having a gun stuck in his face?
Hell even if Martin for no readily explainable reason ducked out of sight, doubled back unseen somehow, and then attacked the creepy dude that had been following him why pull a gun in a fistfight? Against an opponent much smaller than you?
What's more believable? A mentally unstable paranoiac hell-bent on playing vigilante shoots a kid that struggles away from him or a small kid manages to ambush a paranoid man already looking for trouble using improbable stealth skills but doesn't grab so much as a rock beforehand despite his 'victim' being significantly larger and armed?
The prosecution is contractually bound to pursue a case to the fullest extent of the law, their opinion of the guilt of the defendant is irrelevant. They didn't walk off because they thought there was no case, they walked off because winning would threaten the "Stand your Ground" legal defense. Being incapable of proving premeditation of the shooting isn't grounds for a full acquittal, there are still lesser charges of manslaughter, reckless endangerment, etc. that would normally be sought instead.
The prosecution and especially the jury wanted to preserve the right to gun down potential threats, but whether race has anything to do with it is another matter. Either way, the legal system just got screwed over and now a dangerous nut walks free after killing some kid on bullshit pretenses.