The slaves already did the work on those plantations, why shouldn't they be entitled to keep what they produced? It's quite a different kettle of fish from taking the land from someone and giving it to someone else who was never involved with the land in the first place.

I think it's quite clear that it is unjust to profit from another's work without contributing to the process, ala plantation owners. The easiest solution to that injustice is to limit the profit of that work to the person doing it.

Can you show me a historical example where what I described happened, and resulted in negative consequences? Because I'm not even sure I can name such a situation at all, nevermind the outcomes.