He did not have the right to defend the city and businesses unless he was a police officer for that city. For crying out loud he didn't even live in the state. When did vigilantism become legal in this country?
My state adopted the Stand Your Ground law, but prior to that, if somebody was screaming at me and I didn't turn around and get away from him, but used my gun instead, I would end up in jail for murder. Why? Because in our state you had a duty to retreat. You must (by law) remove yourself from any potential violent situation. Now, STG changed that, but if I seen some gang members in front of my house getting ready to brawl, and I went out there with my gun where several of them tried to attack me and I killed them, that's not self-defense. Why? Because I left my place of safety and deliberately inserted myself into a violent situation that had zero to do with me.