I suppose what bothers me is that the term allows bigots to continue believing that there is some significant genetic difference between African Americans and European Americans based on their races -that is their genetics. Race is a social concept, dividing people according to culturally transmitted classification schemes.
Scientists now know that genetics are the basis of heredity, and that the genetics of human populations today are complicated. (Check out this interactive map, for example.)
Scientists know that Homo sapiens as a species emerged in Africa, and went through hard enough times that the species was reduced to very small numbers from which all modern humans are descended. Thus it is perhaps an acceptable generalization that we are all members of the human race.
While the majority of Homo sapiens remained in Africa, some migrated into the Eurasian land mass and the species spread across Europe and Asia; some humans later migrated to Australia, the Americas and various islands. Thus, I suppose all Americans are all genetically African Americans; we share most of our genetic heritage with all Homo sapiens because we are all relatively recently descended from Africans (at least as geneticists think of evolutionary time.)
Local variations occurred and some as a result of natural selection became common in local human populations. There was most genetic diversity in Africa, the continent of origin of the species and thus the continent of longest genetic history of Homo sapiens.
It appears that there has been some introduction of genes into human populations from non-human sources. Thus it would appear that a relatively small number of genes was introduced into European human populations from Homo neanderthalensus; some of them were sufficiently useful to be retained at least locally; these include perhaps the genes for light colored skin and hair.
Anyone who has watched Finding Your Roots on TV will have a pretty good idea that African Americans tend to have a lot of European ancestors. (I remember a "Black" friend who told me after we had known each other for years that one of her grandfathers came from Ireland and the other grandfather came from Germany; I was kind of annoyed that in public she tended to deny her Irish ancestry -- something that Barack Obama does not do.) So not only do African Americans tend to have European ancestors, European Americans tend to have African ancestors. (My Irish ancestors had the belief that they descended from a people who in relatively recent times migrated from Asia via North Africa to Spain and then Ireland.)
"Hispanics" are even more clearly defined by culture than genetics, since it tends to be their common heritage of the Spanish language that defines the group. Hispanics may trace their ancestry to Spain, but in Spain people tend to be divided into such categories as coming from Aragon, Caatile, Catalonia, the Basque country, Galicia, etc. Historically in Latin America categories such as Mestizo (both Spanish and American Indian ancestry), Mulato (Spanish and African ancestry) and Zambo (European, African and American India ancestry) with torturous nomenclature for different combinations of ancestors. I find it impossible to use genetics as a basis for distinguishing Hispanics from other taxonomic groups of Homo sapiens.
So as long as the United States is stuck with prejudice of one group against another, lets find a better term. We have religious prejudice and class prejudice, why not use terms such as "cultural prejudice" or "ethnic prejudice" instead of "racial prejudice"?
The world's most and least ethnically diverse countries