why do you get to take away that person's rights then? because they took away someone elses rights? Please. that's not a way to solve stuff, and not a way governments should act. if you think a thing someone does is wrong you don't give them a taste of their own medicine, you should instead be The Bigger Person and not do the same thing. especially when it comes to life and death situations and with human rights
Unfortunately being the bigger person isn't always the best option. If a person is doing something that could could potentially earn them the death sentence (like stabbing a bunch of disabled people in Japan), then they deserve it. They don't deserve anything less than to be put down. Humans are highly intelligent, and when they decide stabbing people to death is okay, they're incredibly dangerous. Why let someone like that continue to live and risk them doing that to more people?