Michael Shermer, a famous skeptic, was forced to admit that one of the reasons is that
some of them are true. In his research he found that the fact that some conspiracy theories are real feeds people’s suspicion and makes them susceptible to the belief in others that are far less credible.
We are increasingly herded into taking a hard line on issues which are nuanced. One example of this is an apparent increase in two camps: some people are entirely against mainstream medicine while others will bend over backwards to mount an extreme defense of the indefensible excesses of Big Pharma.