In a long piece at Psychology Today Blogs, Joe Pierre attempts to understand anti-vaxxers. Here’s a bit:
In addition to conspiracy-based mistrust, Matthew Motta and his colleagues explored whether the Dunning-Kruger Effect — whereby those with the lowest levels of actual knowledge tend to have the greatest degree of overconfidence regarding self-rated expertise — might figure into anti-vaccination beliefs.15 Administering a survey to 1310 US adults, they found that over a third of respondents believed they knew as much or more about the causes of autism than doctors and scientists and that such overconfidence was highest when respondents demonstrated low levels of actual knowledge and higher levels of misinformation about the relationship between autism and vaccines.
I commend the article to your attention.
I think it may help in understanding the Trumpettes, as well.