rep·a·ra·tion
ˌrepəˈrāSHən/Submit
noun
the making of amends for a wrong one has done, by paying
money to or otherwise helping those who have been wronged.
I agree entirely that ‘the sins of the father’ can't be addressed by punishing the sons, or the daughters, or the grandchildren, or anyone that wasn't the perpetrator of the wrong. That said, I don't know how people ever got the idea that enslaving others was acceptable. Also, it's not like this was 1000 years ago, and it's still happening in some places in the world now in the 21st century.
Slavery in Brazil didnt end until 1889, making Brazil the last nation in the Western Hemisphere to outlaw the institution.
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I guess the writer does not consider Haiti to be in the Western Hemisphere. Slavery is still practiced there.