It is called punishment. If you cannot see the difference between a killer breaking into a home and strangling somebody to death for their own sick reasons with a government executing that criminal for murder, then you truly do not understand the difference between right and wrong.
It is fine if you are against the death penalty, I am too but for a completely different reason. My reason is because an innocent person might get executed.
I do not for a second pretend a cold blooded murder by a killer is equivalent to a state execution of said killer. I do not have such low respect of victims of crime and frankly I am surprised and shocked you do.