I think this is pretty much like an international court telling Americans, “No more hamburgers. No beef whatsoever.”
I know I’d say, “Really? Seriously? And, where in the Constitution does it say I have to follow some foreign court?”
Having said that, we have ceded our sovereignty to foreign courts by treaty. This is what the UN small arm’s treaty would do, give a foreign court the ability to allow our trading partners to inflict tariffs if local stores sell guns.
I am still amazed that the Japanese have not been declared poachers.