You're describing a couple members of my family except... they don't use any Facebook products. Humans have been surrounding themselves with people that parrot their beliefs for generations; the internet just made it easier for fringe beliefs to reach critical mass.
If it not Facebook, it would be some other medium. What's the alternative, prevent people from talking to each other unsupervised?
If it not Facebook, it would be some other medium. What's the alternative, prevent people from talking to each other unsupervised?