the "heroes don't kill" mantra is something that's spread almost universally through comics, even in relation to characters [like punisher] who kill without giving a shit. he got his ass kicked by captain america because of that fact alone, he's fought spider-man because of it, etcetera. while it's not always practiced as it is preached, it's something of a golden rule in a majority of the superhero community.
the whole "are cops heroes?" thing is something i don't want to get into. police officers don't, or at least are never instructed to, "kill first, ask questions later." guns aren't drawn unless there is a threat, shots aren't fired unless the officer, a fellow officer, or a victim is in a directly threatened situation with a weapon or something similar. and the shots are almost always meant to disarm and end the situation without casualties. SWAT and the Feds and so forth, not exactly the same rules. same with soldiers. that's not what I'm talking about. i mean comic book superheroes.
back to my example, since we're making the distinction between murder and killing, which i suppose boils down to intentional v. unintentional. Madrox didn't mean to kill the guy, it happened on instinct. Rahne didn't mean to kill the guy, she was under attack. Rictor seemed to have meant to kill the guy, but it was in defending his own and Siryn's life. Layla obviously meant to kill the guy, and had seemingly no compunctions about attempting to set Quicksilver up to be killed as well. and Guido wasn't responsible for murdering Dr. Buchanan because he was in some sort of hypnotic/post-hypnotic state. but that doesn't mean those lives aren't lost due to their actions, and there is literally next-to-no reaction about this in the comics. where's this "hero's code" idea when nobody cares they're causing people to die, or outright killing them?
Cyclops rebooted x-force because "x-men don't kill," but House of M Cyke said "whatever rules you place on yourself, they have no place here," or something to that effect. he wanted the assembled heroes to kill Magneto's crew. he also killed Ugly John, a "mercy killing," in New X-Men. i'm sure i'm forgetting something there, too.
just seems like levels of hypocrisy and flip-flopping, and i just want to know who's done it, and if they've done it, who cared?