It's a bit weird from the outside, as a non-american. When I was growing up there was a very narrow window of acceptable ideas in the US, anything else was "unamerican". "The two parties are basically the same" was a cliche when I was a kid.

The reaction to a relatively tiny number of new acceptable ideas in the discourse has been pretty surprising, even to someone who thought they already had a low opinion of American culture.

And yeah, sure, the ad-generated enragement feeds don't help. But it is clearly mostly the small town kid getting exposed to more ideas thing, no question.