The quote "as long as there's life, there's hope" can just as easily be re-framed as, "as long as child molesters are alive, there's a chance they'll do it again." Anyone willing to take that chance? I'm not.
But if you don't want to go as far as the death sentence for someone who hasn't committed murder, there's the other solution of isolating them in a penal colony as far removed from the general populace as possible (i.e. way up in the arctic somewhere, and let them fend for themselves)