The whole notion of 'freedom' is an artificial and very recent creation. We functioned fine as a society for so many millennia with slavery.
In actual fact, there's more 'slaves' today than at any time in history.
For one, legalized slavery in the US - prisoners are forced to manufacture household appliances, number plates, military uniforms etc. If they refuse, they get solitary confinement and other punishments.
Perhaps the concept of 'freedom' is a good one, but it doesn't map in any way to the real world.
It's not like they created the concept of 'freedom' and then slavery ended.