Stopping a crime in progress is not a punishment. We have different measures to stop crime happening now and to punish a crime that happened in the past. E.g. a punishment for an assault is not death either but you are still entitled to defend yourself from one with deadly force. This is because we, as society, place higher importance on preventing the crime than on punishing the criminal post factum. You are free to disagree and not exercise deadly force or any force at all and submit to the criminals, it's your choice.

The social contact granting the state it's monopoly on violence is contingent on its execution of its duty, herein being the enforcement of law.