It's not about acceptance, it's about the underlying logic. You can assert your position all day, I'm asking why.
Why don't you say "Punishment sucks, yes, but that's part of a crime prevention system. Imprisonment does not need to be a part of that system. How hard is that to accept"?
Or why don't you say "death sucks, yes, but that's part of a crime and punishment system. How hard is that to accept"?