It's a long read, but very much worth it. It goes into detail about the types of material these people have to spend all day watching and reviewing, and talks in length about some of the unhealthy coping mechanisms these teams develop for themselves. Lots of drug use, sex in the office, and suicidal ideation.
While the article focuses mainly on Facebook moderators, I used to share an office with YouTube's content moderation team around the time this article came out, and a lot of the article rings true for YouTube, as well. I imagine it's similar across all the big platforms.