So one thing that minarchists claim to be SO NECESSARY that a government or state court system supposedly has, is the "power to pass and enforce legitimate laws."
So minarchists basically say that "state courts are necessary in order to enforce laws, and the authority of the court is the highest possible authority. Without these state courts, under anarchy or voluntarism, there would be no "way of addressing criminals and criminal activites efficiently or correctly."
And then the minarchists go on to pose questions like "What makes the NAP valid at all?" "Why should the NAP be binding on others?" and "Why should property rights be binding on others?" In a non-statist world?
So minarchists are basically saying "The NAP (property rights) is not necessarily valid or binding. That is why we need a valid and binding court system."