So many people would be alive if heroes kill villains who keep committing crimes. for example Jason Todd would have never died if batman would have kill the joker. Heroes like the punisher, wolverine,and wonder woman( at times) have the right idea if their a treat now and don't try to change why not put an end to them one and for all. so why heroes kill is it because they like the challenge the villains bring despite the many deaths( not very heroic), or is it the fame that comes with people seeing you save the day( hope not sense they always go trough them sad moments and almost quit being heroes), or maybe their afraid to kill( if so their not hero material, a hero should be willing to do whatever it takes). Now some villains like lex have help save the world on several occasions, but the threat would have never happen had that threat ended a long time ago. Now i do agree with arresting villains and offer them a chance to reform, but if they don't take it, kill them.