I think I touched on these aspects. Slavery would have to be peculiar to the social structure. That is slaves are only economical when the fabric of the society is at risk. I think the Roman Empire is an example here; for without forced labor, in their eyes, things would not get done, and the social hierarchy would break down. I mean, for them at least, if slaves were freed and flaunted authority where would it end? I think the prejudice there was that slaves were there because they were slaves; incorrigible and not useful for anything other than being forced to work.
If we go the 3I, or its neighbors, there's bound to be pockets of slavery. But for a steller community, one with robots or early android technology, slaves might become rare.
In Hofstede's cultural dimensions theory, Rome was a high power distance culture; slavery was different and slaves there had rights and a place as a family member in households. Even there the economics didn't work out and they changed away from slaveowning to contract labor. Any society progressed far enough to have robots, will also have HRM dow to where slavery is not economically feasible. Slaves are just too expensive for low productivity, it's why modern countries don't have slavery now.