Why do we kill people who kill people to show killing people is wrong? The death penalty should be banned in almost every case, aside from mass murderers and criminals of a similar caliber. And even then, if the person is unable to function in society due to mental issues, then it is the responsibility of the society not to kill them, but separate them and ensure they cannot harm anyone. Additionally, killing them gives no justice, they can do no less harm than if they were locked away, it only makes murderers of all members of the society.