

That’s just being part of a minority no matter where you live. White Americans don’t all celebrate the same things and don’t all talk the same way, with some of them being nigh impossible to understand if you weren’t raised around people who speak like them, yet they’re just called Americans. Hell, if you were raised in the USA and have Danish parents no one will call you a Danish-American as long as you don’t have an accent, but if you are of Latino origins and your family has lived on US soil since before the USA was a thing you will be called a Latin-American. It’s just racism.
Racism, that’s the word you’re looking for! So well implemented that the victims keep it going without any influence from the group that “has the right” to just call itself American without any prefix.