And those unionized workers usually have pretty great benefits, pay, and pensions that they've bargained for because of that.
If their back goes out, the insurance and/or company will have to foot the bill. If the company fails to provide adequate training and safety precautions [within reason] they're highly liable.
This sounds a little like YT is attempting to abdicate responsibility, rather than coming to an agreement.
All of that said, I have no insight into the onboarding practices for a job like this one. Are they trained not only in how to moderate, but how to recognize signs of work-related stress or mental issues ahead of time and given reasonable precautions against causing long-term damage? Are they thoughtfully prepared for some of the content they will have to view? I guess I could look this up myself, but I'm also wondering if anyone here has that kind of insight.