Seems the author thinks that slavery started in the American South. Slavery has been a common institution among all races for as long as there have been people. It was white Christians that finally decided to put a stop to it (at least in the civilized world).
It ought to have died in Christendom with Paul’s admonition “Giving up threatening.” Service was to be VOLUNTARY in Christendom. So yes this was early modern Christendom’s bad. Fundamentalism forgot to be fundamentalist here.