HHD,
I have no quarrel with your point of view, and in fact just a few years ago I would have been quite outraged myself. But in the intervening time I have considered the merits of death vs life in prison without parole, and, informed primarily by Catholic principles, I have come to the conclusion that our proper place as a society is to allow a man his natural lifespan to repent (this doesn't mean he gets out of prison), and to make what amends he can to his victims and God.
My position has undergone a thorough evolution for sure, and with respect to the prosecutors and juries involved in the death penalty decision, I hope they are understanding of Biden's action (even if it was undertaken for cynical political ends).