I don't know. Most likely the majority of Black Americans who are descendants of the enslaved in America.
I am assuming if one does have an confederate ancestor it's not because of love. So, I don't know if and why it would matter.
I am sure I do - but I don't look at them as my ancestor. I look at them as someone who enslaved and sexually violated my ancestor. That's nothing I would be proud of. Nor want to be reminded of by seeing a monument.