> We can give up on them. We give up quicker on lots of people in society, why not someone who is a mass murderer?
Yeah, I know. Ultimately I think my unease here is a kind of slippery-slope argument, and deserves to be taken with the same generous pinch of salt as any other slippery-slope argument.
I suspect that much of the opposition to capital (and corporal) punishment has to do with how strong and visceral a mental impression it makes on those witnessing or even thinking about it. Conversely, I'm sure we underestimate the soul-destroying misery of long-term incarceration, because it doesn't offend our sensibilities as much. Same goes for many of the other people we give up on, which goes back to your point.
In any case, thanks for the thoughtful replies. Being able to have a reasonable discussion on an emotive topic with someone holding different views is always a breath of fresh air.
You are right the deterrent argument is dumb and unsupported.
> it does something bad to a society when "giving up on one of your citizens completely" becomes an option
Human societies have been like this forever, though. Sometimes the protection of the society is more valuable than an individual's life. That stance can be taken too far, but I struggle to see what the point of keeping individuals like Dahmer, Gacy, Bundy around. We can give up on them. We give up quicker on lots of people in society, why not someone who is a mass murderer? They've got nothing to offer and they've given up their rights in taking the rights of and normalcy of hundreds of others.