Some Minarchists/Libertarians think Anarcho-Capitalists look down on them and make fun of them. I can't speak for everyone, but personally, Libertarians frustrate me. Mainly because I see some hope in them and would like to see more Libertarians become Ancaps as I did.
Libertarians and I agree on one major thing that Democrats and Republicans do not. The state is the problem. Republicans and Democrats fight vehemently about issues. But always on how the government should be used in these situations not on reducing its power and reach, or downright eliminating it as I would do.
My frustration with Libertarians stems from this similarity. I have no hope for followers of the two major parties, but if you realize that government is incapable of solving problems, anti-liberty, and evil, why make excuses for certain services? If it's unreasonable to expect the government to provide health care why is it logical to let them have a monopoly on our protection/rule enforcement? Once you realize the government is evil as it forces it’s will on the people, there should be no exceptions. Anything else is simply making excuses for an organization you know to be wrong and immoral.
Government is force. Worse yet it has monopolized “legal” force. Beyond that any quasi-legitimate service they provide is simply that, a service. If it’s a useful and wanted service people will do it without government forcing on us.