It's really something that you may not really think about. But who is checking the posts? For nudity, violence, propaganda or other "inappropriate" content? And how do they decide? Now I guess you could have shown this in a short documentary. But then you wouldn't have all the people who are actually doing this in the movie.
In this case the net or rather social media in general (Facebook in general for being the biggest plattform), has some issues. And it's in countries you may not have heard before. But they unwillingly help certain people there, because they didn't put resources in place to check certain things. And having some people checking pictures all day, may sound fun, but it is also exhilirating to some extent, especially if you consider the quota they have to fulfill and what that amounts to in pics watched and what that means "quality" wise when it comes to the controlling the content.
If you like documentaries and if you have an open mind, you will find many interesting things here ...