Update: Sowell video was monetized. Still hope to hear from @teamyoutube what caused the demonetization in the first place and what “context around the video” means. That’s a new piece of the puzzle...https://twitter.com/rubinreport/status/987401513348845571 …
I think they look at the comments and the type of people who view or share the video. If they don't like what they see, they demonetize the video even if it's not particularly offensive itself.