Pretty weak stuff from Hoppe as far as theory is concerned. He does a decent job of distinguishing Hayek from the Austrian school by mining quotes that express sentiments antithetical to libertarian and anarcho-capitalist views, but there isn't any analysis. I was actually more intrigued by the Hayek quotes.
if they are at least predictable and are enforced irrespective of how the individual would otherwise employ his energies; this deprives them largely of the evil nature of coercion. If the known necessity of paying a certain amount of taxes becomes the basis of all my plans, if a period of military service is a foreseeable part of my career, then I can follow a general plan of life of my own making and am as independent of the will of another person as men have learned to be in society. [Hayek]
The idea that government intrusions into the private sphere are acceptable so long as they are predictable is an intriguing conclusion. If I know that I'll be providing compulsory military service for my country when I turn 18, I'll adapt my planning horizon accordingly and it won't necessarily increase my time preference to the extent that errant and unpredictable criminality and natural disasters do. Compulsory service would be analogous to having foreknowledge of a disruptive business cycle that would reduce one's productivity for a duration of years.
In addition, Hayek insists we recognize that it is irrelevant how big government is or if and how fast it grows. What alone is important is that government actions fulfill certain formal requirements. "It is the character rather than the volume of government activity that is important." Taxes as such and the absolute height of taxation are not a problem for Hayek. [Hoppe]
I don't see how quantity of government activity is irrelevant under this system, which seems to me to be nothing more than an idiosyncratic version of Lon Fuller's theory of Legal Process (formal legality is itself ethical regardless of its substantive content because it confers procedural goods like predictability.) There probably exists a quantity of government intrusion that completely switches off all personal calculation and renders practical economic insights useless. At this point the question of coercion also vanishes because human freedom no longer exists. Here the ground of liberalism erodes and is replaced by the concept of the organism: the citizen becomes a productive tool (an Aristotelian natural slave), a dependent part incapable of self-sufficiency.