You voluntarily contracted with the other citizens of your country to pay tax when you chose to continue to live in your country.
That's a practical fallacy. It's impossible to live in any country where one isn't taxed.
Your parents volunteered and contracted on your behalf when they chose to give birth to you in that country
Kind of like how my parents "volunteered" me to get circumcised. Thanks Mom&Dad.
You volunteered and contracted when you chose to benefit by
No such contract exists. There is no voluntary action when it comes to a forceful extraction. It should also be noted that I've been arguing this point on an ideological basis and not a political one.
and neither do complete free markets.
To be fair, unlike Command Economies, this assertion has no real-world evidence to back it up. The problem with the concept of a free market is that it can never exist with a government. The only "free market" is the one that exists in a state of anarchy.
I would imagine, though, that it would still only work like Social Anarchism at the communal level. As models become larger in scale it is inherently more difficult for people to collectivise. If Tonga, for instance, hadn't annexed Minerva I imagine it would've succeeded, but the success of Minerva wouldn't necessarily mean that the same model would work on a national scale.
Ok, well, you have made one exception, so why not more?
Because the Principle of Non-aggression requires that a 3rd party exists to enforce that principle. Law
is ultimately rooted in concepts of justice, even if those concepts aren't universal. In anarchy, dealing with instances of fraud, theft, murder, what have you would depend on collectivisation, which acts on a mob mentality. A police and justice system must exist to ensure that the rights of all parties are protected, even in the case of those that have violated the rights of others.
Government exists to protect us from ourselves, but the Libertarian argument is that government should exist to protect us from others. That's the difference between Libertarians and Corporate Anarchists.
Of course, you do get some crazies that think non-aggression applies to all cases, even in those of self-defense, but like I said, they're crazy.