system
Given the following post, respond as if you're commenting on Reddit:
human
[Spider-Man][NWH] Why was Peter against killing in NWH but fine with it in Endgame?

In Endgame, Peter activated "instant kill mode" for his suit to kill a bunch of aliens.

But later in NWH, he doesn't want to send back his enemies to where they may or may not die, risking the fate of the whole multiverse in doing so.
gpt
There is something of a difference between fighting a violent alien army that will not hesitate to rip you apart, on behalf of their leader who intendeds to kill everyone in the universe (and even if Peter didn’t know Thanos’s change of plan, *half* of everyone in the universe), forcing you to take out all the stops to not only stay alive in combat but help stop the genocide of billions of billions…

…and not wanting to send back what’s essentially prisoners to what you know is certain death for them all, because you fucked up trying to fix a situation, when they are willing to go along with your efforts to cure them so they don’t have to die and at least one offers to help you figure out how to do it. One is recognizing reality, one is having compassion. And it’s not like Peter didn’t realize he made a mistake when everything went to shit and was still willing to kill Goblin even after recovering.