Quote from "Inside the Echo Chamber" by Walter Quattrociocchi in the April 2017 edition of Scientific American:
"We observed the same dynamics in a study of 55 million Facebook users in the U.S. Users avoid cognitive discord by consuming information that supports their preexisting beliefs, and they share that information widely. Moreover, we found that over time people who embrace conspiracy theories in one domain-say the (nonexistent) connection between vaccines and autism-will seek out such theories in other domains. Once inside the echo chamber, they tend to embrace the entire conspiracy corpus."
My interpretation: Once a person knows they were lied to about vaccines, they know they were also lied to about a whole.lot more.
Doesn't 55 million Facebook users sound familiar?