I'm an ancap and I concede you make valid points here. The NAP is not viable as an absolute principle - it's too easy to come up with counter-examples that violate common sense morality.
But I've written a short article about how ancap philosopher Michael Huemer rehabilitates the NAP in his book The Problem of Political Authority.
Briefly, while the NAP is not valid as an absolute, aggression is usually wrong and thus we should consider an instance of aggression unjustified unless and until it is shown to be justified. Stealing a loaf of bread counts as aggression, but common sense tells us that your're justified in such if it it was the only way you could feed your family.
Still, there is a strong presumption that aggression is wrong, and we should assume state aggression is wrong unless and until it is shown to be justified.
Justification for aggression by private individuals is rare, but it turns out that it's even harder, much harder, to justify state aggression. So much so that those who incorrectly posited an absolute NAP overwhelmingly reached correct moral conclusions on state policies. The Problem of Political Authority explains why stat aggression is even harder to justify.
My article:
http://www.theproblemofpoliticalauthority.com/2015/08/huemer-and-the-nap/
I think the objections put forth by left-anarchists still apply. Right-libertarians will have a hard time justifying specifically capitalistic property arrangements over usufruct within any NAP framework.
Also, I don't think this NAP argument really works against government action either. See my series on ethics: https://steemit.com/ethics/@ekklesiagora/ethics-3-part-series-summary-anthology
Given such a framework for ethics, which appears to be the only reasonable one, it would be possible to reach a different conclusion. If, for instance, humans would be generally happier and suffer less in a social democratic society than in a fully libertarian society, the former would be preferable to the latter.
" If, for instance, humans would be generally happier and suffer less in a social democratic society than in a fully libertarian society, the former would be preferable to the latter."
It seems to me that we generally reject such reasoning as a justification for coercion in private life. Suppose you and I and half a dozen others agree to meet for dinner in a nice restaurant. The bill comes at the end of the meal, and as it happens we have no previous agreement about how the bill will be paid.
Someone points out that Bob is wealthier than the rest of us, and argues that Bob should pay the whole bill since the price of the meal has a lower marginal value to him than it does to anyone else at the table, and thus having Bob pay will maximize happiness and minimize suffering at the table.
In private life I think almost everyone would agree that this reasoning puts no moral obligation whatsoever on Bob to comply, and that it would be wrong to compel him to pay for the others even if that maximized utility for table. Bob seems fully justified in paying for what he ordered and then going about his business unhindered.
Given that we reject this kind of coercion in private life as unjustified, I think there is a substantial burden on the statist to show why similar coercive behavior is justified when performed by government.
A great deal of wealth is unearned income or wealth accumulated from monopolizing natural resources. Furthermore, the accumulation of wealth is only possible because of the framework and institution provided by society, so it could theoretically be justified for society to claim a part of that wealth for itself. https://steemit.com/anarchism/@ekklesiagora/property-as-theft-the-libertarian-socialist-critique-of-property-summary-anthology
It is, but that is a government structure that support that - Remove the structure and monopolizing of resources is vanished.