You can make some sense of it if you read laws/regulations without any sense for the context or scope of a given document.

For example, U.S. Code Title 18 Part I Chapter 2 Section 31 is a definitions section specifically for that chapter, in which "motor vehicle" is defined as "[...] every description of carriage or other contrivance propelled or drawn by mechanical power and used for commercial purposes [...]".

They take this definition and apply it to all US law, rather than the single chapter in which it is contained, and claim that every reference to a motor vehicle everywhere in law only applies to vehicles being used for commercial purposes. So they go around believing that they're exempt from all such laws simply by asserting that their vehicles are non-commercial.