I think this is the (American) white privilege bubble at work, in a different way than usual. Drug use is pervasive in American society, everyone knows this and it's an obvious thing for Facebook to police. Same with violence, racist abuse, and pornographic images. Buying and selling domestic workers, on the other hand, is so far removed from our experience that it's not something that I would have even thought to work on. I know human trafficking happens, in the abstract sense that I read about it in The Economist or The Atlantic magazines, but the idea that people would take advantage of social media platforms to do it still blows my mind.