Media saturation/psychosis driving self-centered ignorance. At first social media - instant validation for whatever wackadoodle idea you've got, criticism pushed away by engagement algorithms, both directly and by the flash mob of supporters they create. And now LLMs which will eagerly indulge whatever nonsense you throw at them, from a position of authority created by marketing ("AI").

I'm sure there are overt foreign campaigns driving these memes as well though. Not so much for the direct goal of spreading measles, but rather to undermine belief in our institutions and create political divisions out of whole cloth.

And this has been festering so long that it has become quite lucrative. Embracing the nonsense and grifting the herds of followers will not only make you a lot of money, but can put you in some of our highest political offices.