"The first anarchist journal to use the term 'libertarian' was La Libertaire, Journal du Mouvement Social, published in New York City between 1858 and 1861 by French anarcho-communist Joseph Déjacque." [1]
The U.S. Libertarian Party's use of the word is an intentional effort by free market supporters to express their support of a certain kind of "hands-off" policy without the baggage of the left.
You're also insisting that "libertarianism"—a political philosophy—tells us anything about morality or ethics. The stance your describing above is actually a deontological ethics which takes aggression and coercion as its principal 'bad acts.' That's a much stronger position than what, in my experience, even U.S.-style libertarians tend to espouse.
Your position is also incoherent, to be blunt. You say that "using force to take property from others violates the NAP." You mean to say that a workers' occupation is an act of aggression or force, if I understand correctly. I simply ask you this: if the taking of property via force is a violation of your "NAP," what do you say to the implicit threat of force which establishes the principle of property in the first place? If your answer is that that force is not used, then I ask you whether it is okay for me to follow you around with a gun, as long as I never actually use it. If your answer is that property is a natural right or a self-evident 'thing,' I ask you to please explain why you feel this way.
I don't want to start a political flame war, but these are the issues at the heart of the article's claims. I'd love if you'd be willing to engage.