That’s the Anti-Vaxxer Party, of course. The answer is simple: the Reactionaries have become the predominant faction in the party, and they are faux libertarians, opposed to mandates from a government that doesn’t embrace their values. Refusing the vaccine is just the latest, and most egregious, of a series of actions they have taken that are against their material interests in order to stick it to the man.
The GOP needs their votes, so they will not condemn this kind of stupid and reckless behavior. As with the riot, however, acquiescing to the extreme right carries its own dangers. Those of us who took the vaccine are getting fed up, and we vote, too.