"not thinking"
It's not so much that, as Wrong Thinking. As humans, we are supposed to employ Critical Thinking, but it isn't instinctual, we have to learn it. Just as importantly, we have to hone our Critical Thinking Skills, and use them constantly. That's how humans are supposed to think.
But if your education didn't include solid Critical Thinking Skills training, then you have a major hole in your ability to process society. That intellectual vacuum wants to be filled by something. Some people don't fill it with anything, and they bounce around making one stupid decision after another. Others fall under the spell of propaganda, which Critical Thinking Skills are particularly successful at resisting, and become radicalized in some way, such as MAGA, or ISIS.
Conservatives have been historically hostile at Critical Thinking Skills curriculum in schools. The Texas Republican Party even once put it in their official platform, explicitly stating that they oppose the teaching Critical Thinking Skills. Imagine creating an official policy that states that they oppose the teaching of PROPER, EFFECTIVE THINKING?
The MAGAs are literally creating a system to deliberately make their constituents more stupid, and vulnerable to manipulation. It's hard to imagine anything more diabolical than that.