Bonded servitude (the superset of slavery) has been a universal thing throughout civilization, even though we have been dreaming of non-stratified societies at least since the enlightenment, and the occasional heretic / blasphemer / impious philosopher since the classical age.

So when we talk about peonage (bonded servants) in civilizations, we compare like to like, say slaves as they were regarded under Roman law vs. serfs during the middle ages. It's messy. We don't have slaves officially in the modern United States, but we do have forced prison labor (which we treat worse than Roman slaves) and we have child labor and immigrant labor, but these are thanks to blind spots in law and enforcement... but that means we have blind spots in law and enforcement were atrocity can (and often does) hide.

So slaves were better off in the Roman age than they were, say, during the Sugar plantation age here in the Americas. Peasants in the middle age had more rights but were just as bonded, and modern court systems emerged because letting the local lord adjudicate based on his gut feeling (oft while he was inebriated) resulted often in miscarriage of justice.

In the meantime, yes, we still fantasize about creating a system in which the lowest laborers can actually enjoy their work, and don't have to worry about precarity of food, housing, health, etc. We're totally not there yet and should be further along than we are.