I agree stand your ground states that. And in the scenario that I provided in my previous post, if I scared away the intruder and then followed them around the neighborhood, and they pulled a gun, I could shoot to defend myself. But it would be a self-defense issue for the courts to decide; it would not be a stand your ground issue. And even with my self-defense claim, I would no doubt have some legal liability in the matter once it became known that the immediate threat had left but I chose to pursue it.
Now, maybe GZ did feel he had to use force to protect himself once the fight started. I wasn't there so I have no way of knowing one way or the other. But even if this is so, it would be a self-defense issue that has nothing to do with stand your ground, IMO. And GZ would have some liability in that he was not in harm's way until he decided to put himself there. He wes told LE was on the way and he did not need to follow Trayvon; he followed him anway.
Trayvon may have been perceived as a threat by GZ. But he was not an immediate threat, as he was walking away from GZ. If Trayvon at some point became an immediate threat to GZ it was due to GZ putting himself in that position.
There are two possible defenses here, IMO: Self-defense and stand your ground. I do not feel that stand you ground applies. But that's my opinion based on what we know currently. My opinion may change later, or it may not.
I really don't think it matters whether GZ put himself in that position or not. It is all about what happened after the physical contact. IMO