A very common fallacy used by propagandists has the structure:
- Person A presents fact X as support for a theory T that person A tries to prove, adding continuous suggestions about a conspiracy, but
- Person B doesn't know fact X,
- Person A claims the media are hiding fact X because they don't want you to know.
- Since person B didn't know about fact X, he now feels it is true that there is a conspiracy to try to keep X secret from widespread knowledge.
This applies even when X is public knowledge for those continuously involved in some topic.
This fallacy portrays fact X as "just another proof" that the worldwide media is being controlled by governments or elites, X is morally bad, they are consistently lying to you, etc.
However, although there may be examples of this happening, it's not a logical argument because there may be another explanation for why you don't know fact X.
Does this fallacy have a name?
NOTE: It's important to note that this fallacy is made by B himself, not A. A isn't giving any explanation about X's secrecy, he directly claims that "X is being omitted by big media". Person B is who unconsciously reinforces A's axiomatic claim (media is hidding it) by adding a premise based on his own experience (I'm surprised by not knowing it). Why B relates his surprise of not knowing it with the validity of being hidden?
A. Due to A's suggestions, B has been biased and fact X is now temporarily attached to "secretism" in B's mind, which makes him forgets during the course of A's explanation that other causes are possible, like for example X not being relevant at all.
B. There's also an unconscious sense that, even if person B doesn't watch TV or read newspapers, and because we live on a strongly interconnected social world, the relevant points of what big media say should "reach me" some way or another, through friends, family conversations, social media posts, etc; a false feeling that "widespread info unavoidably will fall towards me too" just because I live connected to the world and not in a cave.
X is being hidden is a B's unconscious (and fallacious) personal conclusion matching A's claim in response of his suprise after knowing the important fact X.