Have you considered that A4T and others whom you are trying to "enlighten" don't derive pleasure from the pain, suffering or humiliation of those who meet their just ends, but from the notion of justice served?
In my experience many of the supporters of the death penalty want to watch, want public executions, want to be the administrator of death, others want to perpetrate violence and savor the gore. Of course, some are appropriately solemn in their support of the death penalty. Those with a sadistic streak need it pointed out to them.
btw, eye for an eye is sadistic or just feeble-minded.