Slavery existed everywhere, from the beginning of the existence of human beings. No one group bears the whole responsibility for it.
If everyone who can claim historical or ancestral slavery were permitted reparations, everyone alive would be paying them.
Mine were Scots Irish indentured servants. I can assure that if they were mistreated while fulfilling their obligation, the perpetrator would have not survived.
In addition to having ancestors who were slaves, the author likely has ancestors on the other side of slavery, capturing and selling Africans to be sold into slavery around the world.
I certainly won’t say her slave ancestor was lucky to be sold to the west, but had he been sold into Arab/Muslim slavery, he might have been castrated. And if not, highly unlikely he would have been allowed to breed, as slavery wasn’t inherited by children in the Arab world. She probably wouldn’t exist.