One trouble with the term "African American" is that it is too wide. How about an Egyptian or Algerian Arab who comes to live in the U.S.A.? ... African-American? What about a South African (Afrikaner)?
As for slavery, it is the disgrace of the white people, not of the black. And only a portion of the whites, at that.
The term negro remains in the name of the United Negro College Fund, as the term colored still appears in the name of the National Association for the Advancement of Colored People -- both highly esteemed organizations. Therefore these words should still be acceptable in print and in song.
There will always be people who are searching for any occasion to be "offended", as a way of drawing attention to themselves or to their opinions. However meritorious their position may be, the very negativity of this attitude weakens their case. It is all too easy to ignore a whiner.
A very small minority of Jews have adopted this approach, reacting violently to any perceived anti-Semitism. The Jewish people are now comfortably established in American society, where their culture and religion are welcome, and they really have little reason to complain.
A case might be made on historical grounds against the term Indian, as used in North America. The origin of these people is not established but one thing is certain: they are definitely not from India! However they face five hundred years of literature refering to them as Indians, and it may take 500 years to change to Native American.
I think Jed Marum, the Civil War re-enactor who has some experience in this, commented on the importance of context. If a song is hateful, it shouldn't be sung at all, and if it is friendly, it can be sung with its original text. And I would add, with a smile!
Thanks to everyone for their input. == Johnny