I think a lot of it is just reactionary thinking to gun control, exacerbated by the people pushing gun control doing a terrible fucking job of it and feeding the outrage loop.

Someone pushes some dumb law that makes it so only the rich can own a certain accessory or whatever, gun nuts get big mad, it solves nothing and school shootings continue because it did nothing but annoy gun owners while everyone refuses to address the socioeconomic and cultural roots of domestic terrorism in the first place because that’s dangerously close to S O C I A L I S M (aka the government doing stuff)

Toss this all into a general culture that views overthrowing an unjust government as like, the coolest thing you can do, because it is, and you get loser grandpas who maybe once got to be a slave soldier in Vietnam getting gun tattoo eyebrows.