GZ didn't "stalk" anyone (as evidenced by the fact he wasn't charged for stalking by an overzealous prosecutor throwing everything she could at him), he legally mosied down the same public sidewalk that TM went down. He had every right as a resident of the neighborhood to utilize that thoroughfare, TM had the same right to do so.
No crime was committed by either individual at that point in time. NONE. Exactly what happened next is known only by one individual...GZ. And according to the one person that knows exactly what happened, it was self defense. The jury believed it enough to put him back out on the streets. Any conclusions beyond that, by either side is wild conjecture and flaccid detective work by a "bunch of retards I wouldn't trust with a potato gun".