I never "complained" that libertarians were not honest. I never mentioned it at all. My view on libertarianism is that a belief that the economy works better and that people's needs are satisfied better when there is a weak government is an archaic belief that has been completely discredited by history. When government is weak, we breed monopolies; corporations exploit workers and the needs of people are not satisfied -- except for the needs of those who have the monopoly power.
Government regulations and laws didn't pop-up from nowhere. Officials didn't wake up one day and decide, 'I'm going to regulate XXX industry.' Regulations came about due to market failures -- tainted food was sold to consumers; harmful drugs made it to market without proper testing -- to name two examples. Libertarianism presumes that we'd be better without regulations and taxes, which is nonsense.
You said, "hardly anyone is willing to make the libertarian argument against progressive taxes honestly". Well those that won't present it it "honestly" must be some of those doing it dishonestly, correct?. Who is it that is being willingly dishonest other than libertarians...non-libertarians? Or did you add the word "honestly" needlessly and misspoke?
Anyway, the libertarian belief has nothing to do with weak or strong government, it has to do with a government that is effective in preserving the rights and blessings of liberty through a system of justice and managing the commons for its citizens (e.g. national defense) - you know, those "archaic" thoughts found in the "archaic" Constitution that just one post ago you were claiming to be in defense of your "Americanist" ideals.
And when government is limited to its role, it does not "breed monopolies". It "breeds" monopolies when it grants licenses and charters to the few to protect them from competition, e.g.; the US post office, the local sanitation company, the water company, taxi services, gas and electric companies, the former telephone companies, and the biggest monopoly of all … the US government. There are few natural monopolies and those that are, usually without much question, eligible for regulation.
Moreover, a proper government understands that the needs/wants of the people are served when the blessings of liberty are protected - there is no higher expression of satisfying what people individually need and want than in the marketplace - free market capitalism in the production and distribution of goods and services is the most efficient form of social production known. Compare that, if you will, to principles behind what you espouse - government as the sovereign running society's parts as if it were a monopoly owner of the nation's capital and labor. Perhaps you need examples: the Soviet Union, Communist Eastern Europe, Yugoslavia Tito-ist Communism, Maoist Chinese Communism, Cuban "socialism", Venezuelan Bolivarian Socialism, Vietnam's communist-socialism - in every one of these examples state authority and economic control was absolute, and all of it done to "meet the needs of the people". Wanna guess how that turned out?
You're correct, "government regulations and laws didn't pop-up from nowhere." Regulations came about because of folks much like you perceive "a need" to start ordering the parts of society they want changed to comply with their wishes, as well as because those regulated wanted to exclude competition and set price fixing for "the good" of the industry. Dairy supports, farm subsidies, acreage set asides, wage and price controls, interstate transportation regulation, land grants to railroads, etc. were all a part of the disastrous attack on free trade on behalf of "general welfare".
Finally, libertarians and classical liberals usually have no objection to justice in transaction; anyone who knowingly creates and sells tainted meat or harmful drugs to anyone is guilty of fraud, or worse. Moreover, it is generally recognized that the market works best under perfect information - to that end, a government that supports such is desirable. However it is highly dubious that most of regulations created to prevent dangerous food products are necessary, or that government testing is a substitute for liability law and truth in advertising.
So the "archaic" idea of freedom, living in a free society, has not been disproven by history - it has been confirmed by history, which is one reason Europe in general and its English emigre dominated colonies became far more prosperous and advanced than those societies who had no respect for human rights.