Slavery comparison WoT and real world
The selection of Earth comparisons is arbitrary, there would be many more options, but I already have column squeeze.
I think damane indeed is the worst, because you would still have your conscience, yet are forced to harm others, and you actually have to do it. The suldam cannot remote control you. So it is on you (although forced) and you have to witness it.
For power hungry darkfriends though the problem is not harming people, but not being able to decide who, when, how and where.
Compulsed and turned, you are supposedly already gone. Although with turned it would be possible that you are imprisoned in your head and remote controlled by a dark handler entity in your brain.
And the dacovale are worse off, than the typical Roman and US household slaves, they get embarassing "uniforms" and have to prostrate themselves daily as part of the job. Might hint at extra cruelty on galleys and in agriculture too. Like have to throw yourself to the ground if some blood passes, and it is your problem, if it is an irrigated field and you drown.