I think the logic is something like this: People who do wrong should be punished. Otherwise, they will continue to do wrong. The wrongdoers, most likely, aren'

I think the logic is something like this: People who do wrong should be punished. Otherwise, they will continue to do wrong. The wrongdoers, most likely, aren't going get prosecuted by the relevant government officials and the police aren't going to investigate. The best way I have to punish them and prevent further crimes upon the area in which I and my friends and family live and work is to use a gun, as this is quick, highly punishing, can be explained by self-defense, and used with minimal danger to myself.