@rebel16 It's not really about killing him. It's about the author's intent. I mean, sure, a lot of arguments could be made for offing the guy. But I don't think anyone can argue the sequence of events isn't
funny, both literally and as a critique of the scene. They stop his scheme, and then out of nowhere declare "now that you learned your lesson stop doing bad things."
I'm sorry, did he? Did he show a moments remorse, or even a willingness to stop what he was doing? He hadn't spoken a single word or even looked them in the face to give such an impression. Through the whole thing, he had been nothing if not obstinate. I think this wouldn't even be a discussion if instead of making that boneheaded leap in logic, they simply took the Cafus, said "You're a real piece of shit, you know?" and walked away, showing us he has indeed lost everything, and let him reach the conclusion that maybe a change is in order on his own.
You don't look a serial killer in the face, say "stop raping and murdering 12 year old girls please. now that we found you, you learned your lesson. stop it." and walk away. He's probably going to help himself to a few more just to spite you. Do they gotta kill him? No. Just don't write the characters making fools of themselves like they're actually saying something profound and expect the audience to resonate with it.