There are a lot of people in the medical field who buy into this bullshyt. A lot of doctors and that probably surprises people but what people need to understand, all this is more indicative of a cult mindstate instead of simple disagreement with politics or in this case, science. It was very telling that most of the flags you saw were not American flags you'd figure "patriots" would be carrying but instead was mostly Trump flags.
People in cults let the following and adherence to the cult override everything in their lives. Even for people who are supposed to believe in science, the indoctrination such as it being false or faulty science that reinforces their biases politically blind them to what they learned in school. It is easy to dismiss these people as all being stupid but it is deeper than that.
Just to drive the point home further, one of David Koresh's biggest supporters during that whole thing was one of the biggest lawyers in Fort Worth. He had money and I think if I remember, he went to like a really elite school for law school but he decided to follow David Koresh and die in a blaze of fire in the compound with him. All that education and assuming, intelligence, didn't prevent him from buying into insanity. There is something else in the human mind that makes some people prone to this more than others and it is beyond just the "intellectual" nature of the human mind. Probably the same functionality that drives some people to be religious fanatics.