Not that account, but its obvious a settler society such as America has little unity compared to other societies such as Mestizo or East Asian Societies. A lack of religion, social harmony and cohesion, as well as a typical "American" upbringing leaves many feeling alone and without purpose or family. Combined with the growth of the internet, and you have many people who take up horrid ideologies typically at the far ends of the spectrum to fill the void of not having a loving family or a stable friend group.
Its even worse now that the Russians have funded both the NRA and the BLM movement to radicalize both ends of the spectrum.
Also I'd posit that the typical "American upbringing" does little to make you feel a part of in-groups created by traditional American ideals.