Like, I've seen many smart people that are even, in theory, supporting of socialism and against imperialism who are well aware that there is a propaganda machine in the US and the west, who when it comes to anything about AES/past socialist states, they will just regurgitate state department propaganda without question.
Like, even if you bring up, for example, Xinjiang, and how virtually all evidence comes from some really bad research by a guy who clearly has an agenda, they will say something along the lines of "maybe that's true, but that doesn't disprove there's a genocide there". Which... is not how burden of proof works. Mind you, these are also people who clearly know about shifting of the burden of proof when it comes to climate change or evolution, but here? Then it's every logical fallacy, no critical thinking.
So what is it about these things that remove critical thinking from otherwise smart people?
The propaganda is very, very deep set and has basically total cultural penetration. Shaking that isn't about being smart.