Not every implementation of "prisons" in the world is about payback or keeping harmful people out of society, some places focuses on rehabilitation, and more often than not, those prisons are not inhumane at all, because that would defeat the very point of the prison.

Maybe if you consider "Can't walk wherever I want" as inhumane, all of them are, but there is definitely a difference between a prison in Rwanda vs one in Norway, and probably one would feel humane after observing the other.