I understand this thread is a critique of right wing anarchism (which masquerades as "libertarianism" in the United States), but while I love Mill, I have to respectfully disagree with the idea that a state is absolutely necessary for civil society. Although, I'm not saying it's not necessary, I'm saying there's really no good evidence either way. My intuition tells me that it would be chaotic and maybe even disastrous, but after spending five years studying biology, I know better than to overly rely on intuition for something so speculative and untested.
I mean, can anyone here provide a historical example of a society organized around anarchist principles (left or right)? The only good example I'm aware of is left wing anarchists in the Catalonia region of Spain during the Spanish Civil War (1933-36), who were eventually defeated by Franco (who was aligned with the axis powers ... Germany & Italy). And they did in fact have a somewhat well functioning society without a formal state (labor unions organized the society around a theory called anarcho-syndicalism). Granted, those were special circumstances, and I'm not sure if it provides a good example (wartime tends to build high levels of solidarity, and so I have no idea how anarchism would perform under peacetime conditions, although I suspect that degree of solidarity would be difficult to maintain for long periods of time).
I also think Hobbes may have exaggerated somewhat, and I'm not sure if Nietzsche's "will to power" is a basal human instinct, or if it's merely a symptom of other innate features of human nature (such as our desire for social acceptance, our desire for love and sex, our need for security, our survival instinct, and so on). So it may be possible to form a society along egalitarian principles without a formal state ... although I would think it requires a well educated population; and one that's very intentional about making it work (which may be sort of a pipe dream in itself). On the other hand, the very small examples of anarchism in history tend to be overly romanticized by left wing anarchists, so who knows?
But I agree with Cato in terms of the ethics of anarchism, and how it should inform our pursuit of liberty. Left wing anarchists tend to govern themselves using consensus (simply stated, everyone has to agree on everything). If anyone here participated in Occupy Wall Street, you'll know that's a very tenuous proposition (the general assemblies I sat through, in many cases at least, were just a disaster). But nonetheless, there's some small functional examples even today (the Kurds in Kobani and other parts of northern Syria run their society along anarchist and feminist principles, which IMO is a wonderful divergence from everything else we see in the middle east, and it's very functional, although again they're in a fight against a brutal enemy, ISIS, and before that it was Turkey, so can this function in peacetime, I have no idea)?
I like evidence more than the speculation of philosophers. We have no good evidence either way. So I would say that a more level perspective might to be to entertain the idea from an academic/theoretical perspective (as intellectuals like Noam Chomsky do), but also acknowledge that it's a very difficult and tenuous proposition. I guess if some billionaire with an anarchist fetish wants to test the idea and buy up a bunch of property and invite anarchists to be lab rats, I'd be real interested in studying the outcome.
For me, I think it would be great to just get back to FDR style social democracy & get rid of all the corruption (and I'm not necessarily opposed to bringing back the guillotine for one particular head, George bubba Bush)