Are you sure this is tech-related? Professor Peter Turchin, writing in 2012 (I saw a rough draft of the book he eventually published) predicted a peak in American polarization in around 2020, based on trends that go back many decades. We certainly see it on the Internet, but there's good evidence it would be happening regardless, because it can be (and was) predicted based on trends which go back well before the Internet. https://www.amazon.com/Ages-Discord-Peter-Turchin/dp/0996139...