Earlier quoted context omitted.
> I assume you mean USAian. In English, the word American refers to someone from the United States, and almost all of the languages of the world use some equivalent term: amerikkalainen, Amerikaner, Américain, americano, американец , アメリカ人, أمريكي When speaking South American-inflected Spanish, you might use the word estadounidense and not americano USAian is not a word that anyone uses. I don't make the rules.
> n English, the word American refers to someone from the United States, No. It refers to Mexacins, Canadians, Columbians.... The problem with USA expetionalism made clear.
If it makes you feel better, you can tell yourself that American is just a short way of saying United States of American, if you want.