Can a non-white person chime in?
I can understand both points of view. If you’re all “mixed up” and there are few if any customs in your family that stand out as “non-mainstream”, then I can see how going by just “American” makes sense. However, if you grew up celebrating certain holidays, eating certain foods, hearing and saying certain words and phrases that can be traced back to an “old country”, and most importantly, people pick out your differentness, then I say it makes sense to identify yourself as hyphen-American.
I identify myself in different ways, depending on why I’m being asked to identify myself. I don’t speak with any accent (not even “Southern”, really) and there isn’t anything about me that doesn’t scream “AMERICAN!”, but I still stick out as different because of my appearance. So usually, when a white American asks me to identify myself, saying “American” won’t cut it. They’re looking for something more specific. So I usually say I’m a “black American.” I’m essentially saying I’m the descendent of Africans and that is why I appear the way I do. My departure from whiteness is not due to Indian or Asian ancestry. But to African ancestry.
If another black person–anyone of the African Diaspora–asks me “what I am”, I generally say, I’m “African American.” Because usually black people can recognize my African-ness. They are trying to pinpoint a particular culture, and most black people know what I mean by “African American” (as opposed to Haitian, Jamaican, Nigerian, Ethiopian, etc.). Or maybe they are trying to figure out (coyly) if I’m biracial or just light-skinned. If I were biracial, I’d probably say, “I’m biracial, but identify as black/African American.” But because I’m not, I just say, “African American”. That’s usually sufficient.
Growing up in the South, where the world was “black” and “white”, whites didn’t do the hyphenated thing and I wasn’t constantly asked “what are you?” When I moved to New Jersey, this no longer held. There were plenty of people who were “mutt” whites, of course. But you could quickly tell who were “mutt” whites and whites who had grandparents who were right off the boat. They would even do the same code-switching that black people often do. So in my eyes, that marked them as different; if they chose to go by hyphen-American, it would have made perfect sense to me. Just as it made sense for me to distinguish myself from folks with family from the Dominican Republic, Puerto Rico, Haiti, and Egypt–even though I superficially resembled all of them in appearance. It’s not being divisive. It’s just a realization that there are different ways to be an American. I don’t see this as being a bad thing.