I think OP's point is that personal remembrance, direct knowledge/witness, or subject matter expertise is not a requirement when it comes to defending one's strongly invested world view. Instead of looking at evidence, people start with a vague belief about the world and then draw the lines between everything that happens and that world view.
For example: "There are inscrutable elites that operate in secret to control the world." This is a vague and close to impossible-to-prove assertion, but people believe it strongly, and they use this world view to explain everything they have questions about. JFK was obviously assassinated for going against the Shadowy Elite! If you take your belief as a given, many wild explanations simply follow logically. 9/11 was orchestrated by this Elite to [do whatever The Elite does, there are a wide range of speculation even among the "shadowy elite" believers]. COVID was planned by The Elite. It goes on and on, and everything makes sense when you're working from that one assumption.
If you argue with someone against any of these particular things, you're not going to get anywhere because disproving even one of these calls into question the world view that all his other beliefs are pinned to.
EDIT: Parent commenter I see what you're saying now and yea I totally agree!