rage-farming as a genre of syndicated media (think: Limbaugh, Hannity, InfoWars)
selling fear becomes huge moneymaker for opinion programmers (Limbaugh, Hannity, Carlson, etc)
politics as a staple on social media comment threads
offshore groups (like troll farms, etc) posing as domestic political actors, targeting particular demographics
Ready access to guns is of course a problem, but it’s probably made worse when all those folks with ready access to guns are bathed in fear and loathing 24/7 by millionaires making lots of money telling them things to make them or their families afraid or angry. Just a thought