Why in the world do you believe that? Do you buy the goods and services you want from stories or do you have a habit of taking them without paying? It's silly to suggest that all of society can function on a voluntary basis and yet government can't get even gets it's funds voluntarily. It's like all of society is civilized and people want to work together generally speaking until the government comes along and provides them roads. Then again, I imagine plenty of people have no willingness to pay for stuff they don't want, but then, we get into the problem of how it is right to force them to pay for it anyway. It basically becomes the argument of I want this and it doesn't matter what you think, which is all around crap.
Because I have never known a long term, stable society predicated on voluntary taxation or contributions or otherwise a wholly voluntary basis (to be clear, I have never made the claim such a voluntary society could work either; maybe on a very micro scale such as a kibbutz or commune, but beyond that, forget it). I have repeatedly asked for examples of such, and you have failed on every occasion to provide them.
If such things worked, then huge swathes of Africa would be living in relative prosperity rather than violence, instability and desperate poverty. The fact is that there will always be people who will do as they please and take, murder and steal for their own benefit without regard for the lives, happiness or well-being of others, and there needs to be a rule of law to regulate and marginalize this behaviour. The non-aggression principle that Anarchcaps and the like love to tout is a lie and complete fiction; enough people are assholes, egoists, sociopaths and psychopaths of various stripes that it just doesn't work. Anarchy and voluntarism feature the same deluded optimism concerning human nature and humanity as communism, and both fail utterly for the same fundamental reason.
A fraction of your income? What do you consider a fraction?
Anything less than 100% is fractional. Personally I don't have an 'ideal' number for a tax rate of my bracket to throw out off the top of my head if that's what you're looking for; that's more the purview of specialized economists than kneejerk napkin estimations. Approximately though, it would not impede my quality of life in a material way (i.e. I can comfortably afford the necessities, entertainment, provide for retirement assuming a reasonable timeline and averaged rate of return, and some luxury goods and services after tax).
The government taxes everything from the products you buy to your home and investments, and then for some reason taxes your income on top of that. How many times do you think I'm taxed for the same income earned?
I wouldn't know.
And don't even get me started on the warlord logic and how flawed that is. The difference between the government and a warlord is the difference between a beach ball and a marble.
You're right, they're not comparable: feuding warlords create instability, guarantee no rights and freedoms, routinely seize, violate and destroy people's lives and property without due process, feature inconsistent if any rule of law, and stem from power vacuums, such as that created by an ineffectual and powerless government. By contrast most modern democratic governments guarantee rights and freedoms, have generally consistent rule of law, and foster prosperous societies on the whole.
What does the word functional mean to you? You see, I imagine a person like yourself would define that word very differently than I would.
Probably, which is why I asked you first.
See, here we go, you spout your is the superior POV and thus you are morally correct in lowering the welath of those you deem "undeserving".
Evidence based POV with the objective of optimizing outcomes for the greatest number of people.