That argument and viewpoint doesn't wash any more,
Had they shot him after seeing a gun and it pointed at them, then that's reasonable. To shoot the guy based on the fact he might have had a gun plays right into the rhetoric of racists. If it was a white guy, would they have assumed he was going for a gun, and shot them? From everything we know about this situation was that this guy was trying t break up a fight between two women, and was trying to get his three kids away from the situation. Shooting based on the info we have and what we've seen, no one can say this was justified.