I understand that you're saying:
> [slavery] is not representative of farming as labor
But I disagree, since it clearly has been. Military, prison, servitude, employment, even the tyranny of "the man of the house" - all these hierarchical authoritarian social structures (whether or not they were ever noble or righteous, or useful) have improved ethically over time in the lives of those subjected to the violence of these systems - the conditions used to be a lot worse, across the board.
Labor is not solved in terms of ethics, but it's a lot better now.