Like many types of paranoid thinking, conspiracy theorists fasten on unimportant details and regard them as key. The tax protestors get caught up in your name being in all-caps for Social Security, which means that it’s not you but some artificial entity. Their proof that the income tax is illegal hinges on a delivery of a document to the State of Ohio that did not happen in the right way, even though everyone in Ohio knew about it. There is the nod and the knowing look that they can’t be fooled. The real truth isn’t known to all those other people, who are blithely going about their business thinking everything is just fine, and completely on the up-and-up.
The belief that the real answer is hidden, being kept from the masses by nefarious actors precedes the actual explanations. They don’t come to believe that doctors are hiding cures because they are presented with plausible evidence of same, but because they don’t trust doctors, or perhaps anyone in authority, and someone tacks a specific example onto that. All-caps often figure prominently in their explanations, trying to impress upon you the importance of this particular set of details that they are now pointing out to you. So that you’ll KNOW.
I keep forgetting that this applies to history in general, when people are dead-enders for lost causes. There is the same focus on petty details that you are supposed to understand are actually important. Holocaust deniers will do this. Not all, certainly. There are representatives of every idea who can appear plausible. But when you come upon them, those small details and all caps are frequent. It should be noted that the small details are often quite true. And certainly, there are times when small details matter, as every reader of mysteries knows. “Yes, his father cannot have been in the Christmas Revels at Bath in 1942, because the Royal Fusiliers were in Tunisia at the time.” But forest/trees is the repeated issue. The King James only people are sometimes like this, as are those telling you that the Catholic Church is the Antichrist.
This type of reasoning can also infect discussions that are not unreasonable in themselves. One will often hear the claim that the Civil War was not about slavery. I think that is ultimately wrong, and the evidence against the premise is substantial. Yet there are genuine arguments in its favor, not confined to unimportant details. Nevertheless, there is a high percentage of people making the argument who do get lost in the weeds, unwilling to come out.
I have found them impossible, because they are not actually operating from facts, they are using facts in the service of some emotion-driven or cultural belief. The effect is the same as in CS Lewis’s belief about hell, that all the doors are locked - but from the inside only. The Dwarves could taste the banquet if they could only choose to.