If you cannot distinguish between what two (or one) persons do in their home, and what people do while operating a vehicle on a public roadway, then I have great fear for the conservative movement.
Using small words: I own my home. I don't own the road, the People (through their agent the State) do. In order to use my car on the road, I agree to the People's rules. I don't have to agree to anyone's rules to use myself.