The point, these memes argue, is that the number is small, and therefore Black people should not hold animus toward White people for the crimes of their ancestors.
See how this just glides past assuming that (a) it's okay to "hold animus" toward someone because of the "crimes of their ancestors" (as if you would even know what their ancestors did!), and (b) all "White people" [sic] have slaveholding ancestors?
(I'm white. I live in a state of the old Confederacy, but I grew up in the North. All my ancestors emigrated from Europe to northern states, about half of them after the Civil War. How many slaves do you think my ancestors had in Wisconsin and Dakota Territory in 1870? Uhh, that number is ZERO.)
Endorsing racism and racist assumptions is not cool, and that's what this article does.
It's Snopes. Lying is all they know how to do.