Some background on the Neighborhood Watch case, so it does not confuse things:
It’s not relevant to the Stand-Your-Ground law, although the perpetrator claimed it was. In this case, said Watch Captain hunted a specific individual and basically murdered him in cold blood. The Police then completely boned the case from start to finish, to such a degree that what should have been an open-and-shut case is not probably unprosecutable. But all there was, was plain murder and bad policework.
Yes, the murderer claimed he was acting in self-defense. Why not? He stood to lose nothing by doing so and clouding the issue. In that respect, at least, it is similar to the case under discussion.