What is with the drivers out here lately?

Two days in a row, I'm just driving normally, not cutting anyone off, not brake checking anyone, leaving the left lane open so people who want to go around me can. Two separate old white dudes in pickups on separate days go around me, and then start mouthing something angrily, like yelling with hand gestures. I literally didn't do a thing, was driving the same way down a straight road for miles minding my own business.

The only thing I can think of is we have a pro California sticker on the back of our car. Could this be what's getting people so worked up? Like do people hate California so much that me just existing annoys them that much? Because good God if that's the case, these people are children.