Criminal rights?

Ok so if you murder someone, you deny them their right to say no to your murdering them, their right to exist, their right to etc and yadda yadda. So why do we give rights at all to murderers and rapists? Some of them kill children. They kill kids with every bit of aggression and hatred that they would an adult. Feed them to lions as the romans used to do to christians. Fill professional athletic stadiums to brim with people and let the people watch free pf charge. They are entitled to this as citizens as public hangings were once popular in town squares. It would fulfill a certain morale. And anyone serving 12 life sentences and no death penalty should be exposed to experiments with products used by humans instead of animals. The surviving Manson family for example. Male products on the men, female products on the females. Anything from natural male enhancements to abortion pills. You decide.