In an anarchic society with no government to protect people, the people would pay whoever likes this line of work to protect them. A system of private law enforcememt could emerge out of anarchy. The interactions between different law enforcement agencies (whether with simple agreements or third party private arbitration courts) and the different internal rules would create a market in which consumers are free to choose what laws make sense for them, or at least where laws converge towards what all people want. "The Machinery of Freedom" contains a more in depth description.

As an addendum, in an anarchic society victimless crimes wouldn't be crimes so there would be significantly less people to imprison / execute / send to force labour camps.