The USA is one of the few countries on earth to use a continent name as part of its country name. Yet you don’t see too many people saying South Africa should refer to the entire southern part of the continent.

People also don’t seem to have a problem with using “US”, which overlaps with Mexico aka EUM (or USM in English). Like I said, it’s mostly a language and cultural divide. Are you advocating that Canadians or Mexicans should say they’re American, even if they don’t want to? In the English speaking world no one other than the USA says American.