We consider psychological stress in a different category than physical. It's seen as uniquely cruel because it corrupts intangible things like identity and humanity, not knees and joints. We get physically laborious jobs... They're grueling but we understand the inputs, outputs and the toll.
Putting someone in front of the worst of humanity (CSAM, murder, suicide, bestiality etc) for 9 hours a day at $2/hr seems inhumane because it may very well change who they are and how they think. Add to that the fact that it's sponsored by the richest companies on the planet for the benefit of the upper half and you get the current, IMO justified, criticisms.
Putting someone in front of the worst of humanity (CSAM, murder, suicide, bestiality etc) for 9 hours a day at $2/hr seems inhumane because it may very well change who they are and how they think. Add to that the fact that it's sponsored by the richest companies on the planet for the benefit of the upper half and you get the current, IMO justified, criticisms.