system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: Within the world of comic books, it should be totally fine for all superheroes to kill.

This one's not that serious, obviously.

I've thought about this for a while.  Much is made about Batman and Spider-Man having codes that prevent them from killing.  As far as I know, those are the two that have never killed (in modern incarnations, Golden Age Batman killed).

It just doesn't make sense to me.  If Bruce Wayne and/or Peter Parker were drafted in a war, and handed a gun and told to attack the enemy, they would probably kill.  If not, they would likely endanger the lives of their men, and possibly the world.  What would they do instead?  Would Bruce be throwing Batarangs to knock the guns out of the hands of Nazis, and then run up fast and punch them before they can pick up the gun again?  Over and over?  If Peter is in a plane, is he gonna open the thing and hang his arm out to web the enemy planes, and hope they can land safely?

If a cop came up to a bank robbery, saw a jittery maniac reach for a gun, facing civilians, he would kill the potential murderer and be called a hero.  But for a superhero, that would somehow be a big no-no.

Batman *knows* the Joker has killed.  He knows he's gonna kill again.  Honestly, he should snap his neck and be done with it.  Now, there's a slippery slope argument of "where does it all end?"  Easy.  He's moral enough to know the difference between Paulie Pickpocket and Jerry the Junkie, and Ra's Al Ghul, Killer Croc, etc.  Look at the name!  Killer Croc!  He's not Bootlegger Croc or Illegally Downloading Croc!

Arkham Asylum has the security of an open-air playground.  It's just a matter of time before Joker escapes and blows up a bus full of nuns or something.

I played the Spider-Man game for the PS4 and there's a part where a certain character kills a mobster that was proven without a shadow of a doubt to have murdered several people.  Spidey was dismayed at this.  Why?  Like Tommy Gunn was gonna give up his murdery ways and cure cancer?  That city is so much safer for him being dead.  Spider-Man should at least be indifferent instead of actively upset.

I think that's why there's never been a concentrated effort to get rid of the Punisher.  If Cap or Iron Man were that upset, they'd just pop over to Professor X, get him to find his particular brain waves, then run up and lock him in solitary indefinitely.  But deep down they know... this guy is taking care of business.

Now, I say this argument within the world of comics.  Obviously in the real world, you don't want someone being a vigilante because the real world is messier.  Also, I understand that the publishers (particularly in the old days) wanting to make their heroes more into role models for the youth.  

Anyway fellow nerds, let's debate!
gpt
Superhero comics are a genre of morality play. By and large, they are not meant to be realistic depictions of what would happen if there were a group of people who actually had incredible powers (though there are, of course, a few comics that attempt to tell that story). Like all genres, they have certain repeated tropes and themes that reflect what we as a society value or at least what we tell ourselves we value, and why. Such stories form the basic ideological underpinnings of any society.  

Thus, the reason why Spider-man or Superman or Batman don't kill people is because we imbue those particular characters with certain traits we value as a society, and thus indicate that such a person would reject certain behaviors. Superman is an easy one - he stands for "truth, justice, and the American way." If someone stands for these things, then they can't condone extra-judicial murder, no matter what the circumstances - they have to allow a person to stand trial for their actions. In the case of Spider-man, his youthful cockiness leads to circumstances where his uncle is murdered - thus he learns the lesson that "with great power comes great responsibility" - and therefore you can't abuse the great power you've been given. Who abuses the great power they've been given? Villains.