I like how Asimov put it:
There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge."
It was easy to convince millions of people that they shouldn’t vaccinate their kids. Such idiots can easily be convinced of anything.