Anti-Vaxxers

Once upon a time there was a theory about apparent rising rates of autism, suggesting an excess of a preservative in childhood vaccines as a possible cause. A theory! Didn't pan out.

Can understand parents wanting to to have an explanation, and that provided a reasonable sounding possibility. RFK Jr. was pushing that early on, before The Science said "nah." Somehow that morphed into a general anti-vax movement.

Sometimes people find a thing and can't let go.