What nonsense. Go back 10 generations (about 250 years). Now name your 1024 ancestors. I don't know all of mine, and most don't, can Tim?
Now go back 20 generations. (about 500 years). Now name your 1 Million ancestors. It defies logic that at least some weren't slave owners, and some weren't slaves. I know in my family tree I have both, as many do.
Angling for racist behaviour is one thing, but labelling someone racist because of who their ancestors are is not helpful nor logical.
I am very much against slavery, including those events perpetuated by my ancestors who enslaved other ancestors of mine.
This black/white dichotomy is false - and tries to get me choose one set of my ancestors over others. I refuse to. I am mixed. My DNA shows I am mixed. I look white. I will not disown my African heritage. Deal with it.