It's easy to forget amidst the art and architecture and military accomplishments of the roman empire that it was a particularly brutal slave state.
To be clear, most civilizations of the time had slavery in one form or another, but the combination of the fact that romans implemented chattel slavery where slaves were purely property, and the dictatorial powers the patriarch of the family had over slaves, women, and children in his family combined to have a wide range of permissible behavior towards those who didn't have any social power.
Though to be fair, we need to also remember that just because a state didn't have slavery didn't mean it was a modern liberal democracy. Often, they didn't have slavery in name but the lowest classes of society might as well have been slaves for the level of control they had over their lives.
As an example, after the roman empire fell many European states didn't have slavery but feudalism tied people to the land and gave their lords overwhelming power over them meaning they had a similar lack of control over their own lives.