I don’t think that one can ‘debunk’ a conspiracy theory of this kind. If the conspiracy is that someone powerful wants to cover something up, then an affidavit will simply be disregarded as an attempt to cover up the truth. Any actual or apparent inconsistency in the affidavit will be taken as evidence of the conspiracy.
Unfortunately there is no easy way to really debunk a conspiracy theory like this one. You can get evidence to make a more persuasive argument for or against the ‘theory’, but once it exists there will always be a path of reasoning that justifies the belief.
This is probably why conspiracy theories are so dangerous and powerful, they ultimately can’t be entirely disproven even though they are still unrational and unreasonable.
