One factor I notice is most drivers have their phone up in front of their faces. And at least during rush hour, the biggest trucks are driving pretty slow and the smaller more random drivers definitely correlate to smart phone obsessed drivers. Lots of sudden moves.
Further, people on the freeway totally obsessed with their phones are easy to spot: lane drifting and driving speeds that are typically inconsistent with the prevailing speed of the cars around them.
I drive a Tesla and use auto pilot almost all the time (I don’t have FSD). When you’re going a very consistent speed, the inconsistent behavior of the cars around you feels way more prevalent.
Another potential factor: left lane highway driving. I drove in a 3rd world country this summer and they were very consistent about driving in the right lane and only passing in the left lane. No one at all drove in the left lane. I think left lane driving in the US leads to more risky maneuvers and road rage responses.