Ugur, I adore your writing and hope to see many more articles from you here on Medium. The reason people believe in conspiracy theories is the same reason people believe in gods, goblins, ghosts, and ghouls: it's a simple story, and the human brain craves simplicity. Reality is very complex, and we're not adapted to deal with such complexity. That's why so many people think condensation trails generated by commercial aircraft are "really" poison gas or some similar infantile nonsense. Once again, this would require not only millions of people to be in on the conspiracy (all the pilots, ground crew, companies manufacturing the poison, etc.) but also those very same people to be perfectly happy their own families were being poisoned!
The problem is, the human brain has no mechanisms for consistency-checking. Hence we can believe very silly things provided they are simple-minded enough for us, and we are incapable of checking those beliefs against the other things we think to be true. So we'll always be patsies and dupes, which is why P.T. Barnum was right when he said, "No one ever lost money by under-estimating the intelligence of an audience."