Your assumption of the purest form of libertarianism is honorable. it is people we are dealing with here, and not all are that thinking or honorable---maybe, even the majority are not.
What do you do with those that do what you disagree with?
Blessings
It is true that many are not honorable. You have to remember that this country began with a libertarian philosophy. There was even a time when we had no government that the country prospered, perhaps more than after the constitution was adopted. As government has become more pervasive those less honorable have multiplied. They now have a backstop in government which will support them before it is too late. It used to be that you depended on yourself, and in rare circumstances, on you church and neighbors. This provided motivation to have a good name in the community.
It used to be that those few that violated natural laws would be dealt with by citizens and communities. The early west, without government, was really a much more peaceful place that the eastern cities where you had government police. Jefferson, when asked to participate in the Constitutional Convention, remarked that he wasn't even sure that we needed a government. He noted that the Indians have a highly functional social organization and do not have a government.
It is clear that the unintended consequences of government social programs have contributed to undesirable behavior by many of it's citizens.
What do you do with those that do what you disagree with?
Nothing if they do not violate my natural rights. Defend myself and my property if they do violate. Collectively defend if it becomes necessary. Insurance companies could provide effective private protection for their clients, even with police actions. They would be better motivated to prevent because it is in their economic interest as they provide property insurance. Government does not have that economic motivation as they are paid either way. The market would naturally develop such products if needed.