I think there's a very vocal bubble of lefties who don't like or trust vaccines. Same sort of people who can't let go of the debunked idea that vaccines cause autism, or who get scared about the nasty sounding chemicals in them (dihydrogen monoxide - deadly stuff that kills thousands per year!!!). Those sort of people are predominantly on the "wellness left", and there's plenty of others who hate vaccines for different reasons on the right, but any distinction one might try to draw based on numbers is really a moot point IMO. There's plenty enough of both to go around for any claim that paints one side as anti-science and not the other as silly.Yes, there's always been a "hippie" element of the left, that hasn't changed. I doubt there's much overlap between this hippie element (those who might extol Reiki for anything) and those that admonish people about masks though. In any case, JP makes the element of "the left" that might have had skepticism over vaccines sound larger than it ever was, as if a large chunk of it was anti-vaccine, but fell in line with Big Pharma for some reason over Covid vaccines.
I think there's more examples/types of "science denial", and more widespread, on the right than the left, but yes it exists everywhere.