>This is because American Libertarianism conflates the two ideas "I should be free to do almost anything I want" with "I owe nothing to other humans (and vice-versa)."

Not quite. It confuses freedom with ownership, and thus reasons, "I can only become free by acquiring ownership of more and more of the world around me", with the ultimate conclusion "I can only be free by owning others before they own me."

(That's baked in from the start, since the proprietarian ethic was originally designed for a slave society!)