I guess most people just got used to the cartoons. No hero can kill bad people in the cartoons.
That's just wrong.
Of course it is. They're people and they deserve to live as much as anyone, especially since they can change. Hell, as shown in the example, there was a guy who was going to give up crime and become a better person, but Batman killed him anyway.
I hate vigilante "justice" and that's all Batman, Superman, and all their friends ever are. A pox on them, I say! If you want to help the police, become police ifficers!