And conspiracy theorising, as Jan-Werner Müller and others point out, is part of the inner logic of populism. Populism, remember, is based on the claim that society is divided between “the people” and the illegitimate elites who rule and exploit them.
Not that it's anywhere near the order of magnitude of a threat as right populism, but you see this among tankies as well. By asserting that all facts we have are poisoned, they are able to fill in that space with things like, "North Korean citizens are actually living well."