The whole world uses that term, since the other countries are covered by other terms, or other encompassing terms like I explained already.

When someone says American, what country do you think they come from? You just said you know what North Americans are, so you wouldn’t include Canada or single out Canada there.

American has never meant an all encompassing term for north/central/south America, where the hell did you get this idea from?

North America is Canada and the USA. And there’s also central America, which isn’t included in those two terms.

Just casually ignoring Mexico as part of North America says everything I need to know about how intelligent you are.

Name checks out, you're obtuse.

In English, the correct demonym for a citizen of the United States of America is "American". There have been others that somewhat are accepted but are not universal like "Yankee" which half the population would take great offense to.

It isn't centering the world on us to call ourselves Americans, it's the only thing that works in the language and is accepted by everyone it applies to. Call a Canadian an "american" and watch how quickly they correct you.

I've seen people propose "United statesian" but there 2 problems with that, first it does not flow well in English, second that doesn't actually fix the problem since there's still be ambiguity with people living in the United Mexican States.

What countries have the word "America" in them? How many countries in the Americas are "united States"?
What do you call a citizen of the United Kingdom of Great Britain and Northern Ireland?

For the record, The United States of America is the only country with the word America in it's name. Our immediate neighbor, The United Mexican States, is another country you could, but no one would, plausibly call the United States.

The British isles contains two countries, Ireland and the UK. One of these is the home of the British, and the other would be much happier if you didn't call them that.

Insisting that you not refer to the people of a country by the most unique name in the countries name, because the geographic region has that word in common is ... Odd.