So if the state creates immoral statutes, which a police offer is obliged to enforce, then by that same principal are we all not guilty of the same infraction as law-abiding citizens of the state? My interpretation of your argument is a conflation of individual character with an immoral institution.
There are people who possess native characteristics that would make them good cops and since the state has a monopoly on the use of force they have no choice but to join the state-run police. I take it that you are not an ignorant libertarian and recognize that their is evil in this world which necessitates an entity to protect the peaceful from the aggressive. Furthermore, I will presuppose you are economically literate and understand the value of the division of labor, which would lead to the conclusion that a third-party specialist is the most optimal way of providing for one's security. Therefore, a cop is no more immoral than any business owner who must register his enterprise with the state or face the consequence of imprisonment. Your argument is essentially concluding that FDR has to be a "bad" business because it was approved by the state and that the only way for Stefan to be "good" is to close up shop.
