However...
THE maternal ancestors of Barack Obama once owned slaves, genealogists have revealed.
According to the genealogists, George Washington Overall, Obamas great-great-great-great grandfather, owned two slaves, a 15-year-old girl and 25-year-old man, who were listed in the 1850 Kentucky census. Another maternal ancestor owned two older slaves.
As you also stated they traded slaves, I have read that also. Perhaps also on his mom's side or perhaps on his father's side.
We’ve all been slaves at some point in our ancestral past.