Yeah, this is basically what I'm saying. :) Labour codes are developed over time. In the beginning, it's the wild west. Want to be a janitor and not use any personal protective equipment? Go right ahead! After workers keep getting sick, the government begins to legislate requirements around health and safety.
Awareness of mental illness is a relatively new thing. We'll probably see some developments in this area if the big tech companies continue to outsource moderation at scale. https://www.theguardian.com/news/2017/may/25/facebook-modera... is a nice article that describes accommodations that other companies provide to moderators. They include, as an example, monthly psychologist visits which continue after the person stops working for the organization. They also include training for the person's family and social support groups.