You didn’t answer the all important question: where a govt gets authority over you (which you EXPLICITLY grant in your examples) IF you are NOT delegating your right to self-defense.
You further say:
“However, other people would delegate their rights to government, so government would have the right to use force against me to protect the rights of those others, if necessary.”
This is quite true. And that agent sets the standards by which those rights are said to be violated. If one of its citizens do not face due process before its courts, his rights are being violated. If a citizen is held against his will, his rights are being violated.
You see, for the delegating citizens, its agent possesses a monopoly on the use of force. It does not recognize the NON-delegator’s use of force as valid. As such, your use of force is a violation of that citizen according to the agent. And you will therefore be treated accordingly.
Furthermore, you claim I mischaracterized your argument. You say you WOULD be acting in accord with the standards of the govt - ie you would be respecting all the laws, etc.. You would simply be carrying them all out yourself. Seems like delegation to me (because even if you disagree with a law, according to your example you would still enforce the dictates of the govt to which you do NOT delegate your rights and thus are NOT delegating your judgment of what does and does NOT constitute your self-defense). In other words, you CLAIM you are not delegating your right of self-defense, when, in fact, you ARE.
Put simply, your question is NOT what you purport it to be.
All in all, your question is not about the refusal to delegate the right of self-defense. You DO that by recognizing a govt’s final authority over your self-defensive actions. No - your question is - AFTER delegating your right to self defense, why can’t you be a police officer? The answer is: you can. There are such things as citizen arrest, etc., as I indicated above. Or you could join the police force and recieve training designed to protect individuals from the violation of their rights (both by others and by yourself).
Of course, each of these would place limitations upon the actions you can take. And the reason for such limitations is to better protect the rights of an individual - ie to better guarentee the objectivity of the use of force. Your example of some police officers violating rights (purposefully or inadvertantly) only goes to show how important it is to delegate rights. Such men are trained constantly in means and methods of properly protecting rights (as recognized by govt). Even with all that training, some still violate the rights of others. Those without such training would be MUCH more prone to such violations. So delegation places the protection of rights under objective control. This is true of ALL aspects of rights protection - from lawmaking, to law enforcement, to law judging. A judge who has studied the proper application of law will render better protection of an individual during his trial than Billy Bob from West Virginia (for a number of reasons, including specialized knowledge of the law and specialized reasoning skills etc). Additionally, by removing the players from their own defense, one removes any emotional or personal interest one may gain in the resolution of the case. So delegation places the protection of rights under objective control. etc etc
Thus, the problem with your question is that it is malformed. It purports to be one thing, but is in fact another. And that other is easily answered, as seen above.