I mean Facebook sucks a big one but I fail to see how it's a "monopoly", being the biggest and most well-known doesn't constitute an unlawful business practice. There's tons and tons of other social media outlets out there, copies of copies of stuff. Then again, I guess it can't really hurt, but just passing off WhatsApp and Instagram isn't gonna change much.
I think they mentioned it in the Social Dilemma and I've heard it said before, but that's not entirely true around the world. In some of these developing countries you can get Facebook on your cell phone for free, but pay for everything else. So Facebook = The Internet in a lot of places.