Why do people oppose the death penalty?

As a Christian I am committed to the idea that all people are capable of changing and becoming a Christian. There are no individuals that are outside of this possibility. However, there are some individuals that have chosen to follow paths that take them where no one should go. I speak of sexual offenders. I speak especially of sexual offenses against children, whether boys or girls. The thing that is listed in the story has allegedly been involved in crimes that beg for it to be killed. Even if the thing has had any remorse for its actions, there has not been any change in its practices. If it is convicted of its crimes again, what should be done to it? Feed and clothe it for the rest of its life? Give it counseling so that it can feel better about itself? Give it a chance for parole in a few years so that it can go out and reoffend? What is it about some groups that oppose the death penalty that they would go out of their own way to try to stop these things from being prevented from reoffending ever again? Offenses against children, whether physical or sexual abuse when proven to be habitual, need to have the greatest punishments meted out to the offenders as is possible. One child being killed by abuse should rate in the highest category of murder. One child being sexually abused should carry with it punishment in the realm of a high crime and many years in prison. When these things get out, they should not have the ability to reoffend, even if they were only convicted of one offense. One child killed where sexual abuse has taken place should rate one sentence with no appeal allowed, death. The offenders have taken themselves out of the area of being able to change and taking the offenders out of life will enable more children to live a life that they should have. The death penalty is a harsh thing, but what about that of the dead abused?