Romans did that over 2000 years ago to smoke salmons from the Atlantic shores of their empire (from North Portugal to France) to ship them to Rome. I don't think they were teach by any American....
Regarding the spices, I agree, EEUU have their own seasoning and maybe some cuts, and not really appealing to me. I rather will use spices or cuts from other Americans (like those living down in Patagonia who knows how to roast). But yes, in the US people use their cuts, and in Argentina use their own cuts... what's the point?.
I don;t know what mean the rest of that phrase. I have lived in a few places around the globe (including 4 states in the US) and people don;t really sought after "US" barbecue. Much more sought after are Brazilian or Argentinian meat places, and they have nothing to do with the stuff done in the North of the continent.
cheers