It seems important to consider that some events considered to be conspiracies truly might be conspiracies. I don't think conspiracy theories or theorists are necessarily a good example of delusion, because no one knows whether conspiracies are true, or not. We really don't know. No one knows, no one has a verifiable answer to the question.

If I believe that the news guy on TV is telling me to do *whatever* is something almost everyone (except another delusional person) would agree is provably unbelievable. That's a clearer example of what "delusional" means.