I don't need, legally, to demonstrate any knowledge of this to drive on US roads currently (or even, strictly speaking, to know what side of the road I should drive on).

No, I'm saying that no one should be "concerned that non-registered drivers in one country are being allowed to drive remotely in a different country" because they aren't driving.

It might be for non road code level issues, like physics / crowd ambiguity, where a normal human could fill the missing gaps, US citizen or not.