As always, I welcome any corrections from those who think they can keep this shit straighter than I can, but the gist as I understand it is this:

Many of them actually believe the entire legal regime of the united states is actually a function of private commercial law and that the “real” government is a sort of suppressed by a corporation that was created under its rules, so if they can successfully opt out of their involuntary commercial relationship with the “Corporation” that they are not bound by its rules, including taxes. Because they’re so very smart, they understand you have to be careful, so making sure that you explain that you’re not engaging in “Commerce” as the corporation’s founding document states is important so they don’t rope you back in. The US Constitution gives the federal government the right to govern “Interstate Commerce” so in the spirit of the law being a series of magical incantations, they want to keep consistent. The various US states are either in league with, or under the thumb of, the “corporation.”