Ironically, they think that everyone else is crazy. They've isolated themselves so far from reality that they only believe the clearly false sources that they've come to trust. Meanwhile, they sit in their echo-chambers of like-minded, deluded fools, thinking that everything is so clear to them.
As a specific example, I had mentioned to a small group that Andrew Tate, the infamous misogynistic social commentator, was still waiting for trial in a Romanian prison. One person immediately said that was "fake news" and that they had seen a video of Tate being released from detention where he talked about his exoneration. I gave them the deadpan stare for a slow three-count before saying that they probably shouldn't believe anything from the site that had told them that. They angrily started looking it up on their phone and clearly started to find the truth ... but they never acknowledged that they were wrong (and had been for months).
In general, I've been trying to avoid these sorts of posts, comments on people's posts, or even conversations about these topics. However, I just saw friend post a river of vile and fraudulent misinformation, largely focused on the "revelations" of the above-mentioned Tucker Carlson. I am filled with an odd combination of pity and rage for their pathetic willingness to ignore reality rather than admit they have been duped so badly.