I think there is a big cultural element. Not to say other cultures are immune to conspiracy-theory thinking, but something about American exceptionalism seems to encourage it.
Aren't religions (at least Abrahamic ones) just one big conspiracy theory? People believing in some kind of series of events with little to no evidence? If so I think people globally are apt to believe in dubious claims, aka conspiracy theories.
It's a human thing
Nit: the contention that the world's leaders are shape shifting alien reptiles is an absurd conspiracy theory. This one is just extremely unlikely in the absence of direct evidence.
You're confusing a hypothesis and a belief.
Musk is the new Jobs on HN. His company is beyond failure for he is a holy figure to be worshipped and everything his company does is not the result of the employees, but of his blessing and ability.
Interestingly, I have noticed a tendency for positive stories and statements about SpaceX (and, if I wanted to be contentious, I could even call them 'fanboy' originated) to refer to him as 'Elon', whereas negative or neutral commentary uses the less familiar 'Musk' instead. I'm not quite sure what conclusion to draw from this, though. As for the 'ElongatedMuskrat' user on Reddit, I have no idea...