If the giant football player initiated violence against some neighbor talking at him, insteasd of leaving and/or telling him to f-off, does he not expect self-defense with whatever is handy when he attacks said questioner?
The football player had behavior problems at school; came from a broken family; not surprising he should be impulsive and violent. The shooter was nearly killed by the brute who attacked out of paranoia. GZ is a hero. Evolution wins.