No one has the right to take the life of another. No crime, no feeling of revenge, justifies that. Society has a right and a duty to isolate men and women who have caused harm, and may cause harm again, but to take their lives is unnecessary, unuseful and blasphemous. If you believe in God, life belongs to God. If you don’t believe in God, life belongs to oneself. It does not belong to the state.
usually people with this attitude are for killing an innocent fetus but want someone guilty of murder to live on and be able to cause more harm.