Don't know the history of Obama’s father. Could be he was at some point part of either being a slave or selling them in that part of the world. I don't know.
That MIGHT be true that once in Obama’s father’s ancestry there were slaves. Could have been slaveholders or sellers too. But that could be true for every one of us. The inauguration weepers were crying because he has kinky hair and brown skin and for no other reason. He has achieved nothing.