I believe that we just borrow our lives from God. And He is the only one who have right to take them away from us.
There are some people who dont deserve to live at all, look at a scenario of how a person kills over 20 people for God knows what, This kind of person doesn't deserve to live and must dealt with with the Hammurabi code of law.
It's true they don't deserve to live, but not always it's their fault. We can't judge their actions because we don't know their past. Maybe they diserve to die, but killing them would make you better than them?