What appears to be far-fetched is only so because we have not, as yet, explained it.
If something is unexplained, it's unexplained. That's all you can say of it.
History is littered with the doings and inventions, and theories, of people who were viewed with derision by people such as you: ie, closed-minded and unimaginative, in the sense that they did not possess "the faculty of imagining, or of forming mental images or concepts of what is not actually present to the senses." I'm not talking of your beloved fairy tales here: I trust we can rise above that kind of "rhetoric."
Imagination is a great attribute for the novelist, but it's never been a reliable guide as to determining what's actually the case in the real world. All those examples with which history is littered to which you allude were shown to be true (where they were) by the marshalling of evidence, not by imagination.
Anyway, could you address my points, rather than dismiss them with the usual put-down. In fact, can you?
I not only can, I've done so each and every time this point has been raised, which is a lot. That's why it's such a bore to have to do it yet again.
Nevertheless, since it seems necessary to repeat myself, here goes. I think I'm on safe ground in saying that no, nobody is in the habit of putting themselves in danger - perhaps even of death - for what they know to be a lie or a hoax. The trouble with this simple-minded picture is that it assumes that all human beings have beliefs which are true, when we know that this is very far indeed from the case. It denies, or ignores, human psychology utterly. People are sincerely and honestly mistaken about all sorts of things a great deal of the time all over the place - not liars in any way, but credulous, or poor reasoners. The strength and sincerity of their belief is not in question; but then, that's not the issue, because mere strength and sincerity never made a belief true, did it? People can be staunch, sincere and wrong, wrong, wrong - I can adduce many millions of examples from around seventy or so years ago if you like, not to mention many more both older and more recent. Including some
extremely recent.
People don't put their lives at risk for what they know to be false; on the other hand people can, and have, and do, put their lives at risk for what they believe to be true but which is nevertheless false.