It depends on who was harmed. When countries were banning slavery (or serfdom in places where it was functionally equivalent, like Russia), slave owners made th

It depends on who was harmed. When countries were banning slavery (or serfdom in places where it was functionally equivalent, like Russia), slave owners made this very argument that depriving them of legitimately acquired workpower was an undeserved and unfair calamity for them, and were generally compensated.