There doesn’t seem to be any single, useful guideline in all of this, unless you simply sort people by skin color. Even that is unreliable. I know some folks who’d be called white in the winter and black in the summer.
Sorting folks into continents of origin is barely useful. “My people” came from Europe (Scotland, England, I think) at roughly the same time as the ancestors of most dark-skinned Americans came from places in Africa. Nobody ever calls me European-American, and I’ve never heard anyone call me “that English guy.” Yet, at a glance, my neighbor down the street is dropped into the African-American file folder.
If we call people European-Americans, I will guess there will be some resentment from Italian-Americans who’d rather not be mooshed into the same meatball as Swedish-Americans and Irish-Americans. It might seem sensible to draw an arc on the map, to corral Asian-Americans, until you realize you’ve lassoed the Siberians and the folks in the subcontinent. Until I get to know them, I can’t tell the Indians, Pakistanis, and the Bangladeshis apart, can you? In short, Asian-American is a nearly useless phrase.
How far back should we go in nailing a woman to her roots? This gets complicated. At two or three centuries, it makes no sense to call me an Englishman. At the same range, a black woman is an American, just like me. No hyphens, no distant roots.
Add a few more centuries. If you are still hyphenating, I might be a Viking-American or a Franco-American. The folks we now call Native Americans are Asian-Americans. Not all of them, though. Anthropological evidence based on shapes of flint spear points suggests some of them are European-Americans, from what is now France.
According to genetic evidence, though, we are all African-Americans. Every genetic line can be traced back to Africa. I know, I know. That’s not what the Bible says. Well, it’s not what the creation stories of the Native Americans say either. The Bible says Adam and Eve were in the Middle East. The Native American traditions say we all sprang from someplace in the Americas. Scientifically, that’s incorrect. We all came from Africa.
There is no excuse for all this pigeonholing, my friends. We are people. (I make allowances, of course, for the fact that, on the internet, nobody knows you’re a dog.)