Hmmm. My counterargument would be that the "belief" in this instance is more nuanced than the example: the anti-vax crowd believes that there has been inadequate safety research in the delivery mechanism and scheduling of vaccines. That's a far cry from believing that vaccines cause autism - although the default straw man was "these idiots think vaccines cause autism" a better explanation of their position was "these idiots aren't convinced that vaccines as a cause of autism has been ruled out to their satisfaction and they'd rather be safe than sorry because measles is abstract while autism is concrete to them."

So in this case, the "belief" is limited and hardly black and white. It certainly gives rise to all sorts of spurious justifications ("because Paul Offut is a greedy SOB" "because pharmaceutical companies are getting rich off of the varicella vaccine" "because when you're talking about the herd, it makes sense to let a few kids get autism but we're talking about MY CHILD"). However, that "belief" is, in my opinion, not an "epistemic divide."

As far as "scientific consensus", that's easy to erase by arguing that the consensus isn't scientific. Public health wants the vaccines because one kid dead of smallpox vaccine beats the shit out of thousands of kids dead of smallpox. In this instance, "science" is thinking about humanity, not you. The medical "industry" wants vaccines because they make money off of it. In this instance, "science" is thinking about profits, not you.

My greater point is that while "personal belief exemptions" are what anti-vax people use to get around vaccinating their kids, it isn't really about "belief." Not really. Not unless the "belief" is "government and wall street don't care about my baby" which is pretty easy to prove. Especially when the process involves insurance billing, heinous public health waiting lines and social workers browbeating you to stick your baby six times or else you're a horrible person worthy of scornful eyerolls.

I agree that the author is anti-philosophical. I also agree that the assumption that reasonable people can disagree with each other. My greater point is that it doesn't take a great deal of unreasonability to doubt vaccines and that if you assume that unreasonability you'll never convince them. For most parents, it generally starts with a glance into the maw of modern American medicine followed by a little Googling.

It sounds like we fundamentally agree on this, and we're debating a turn of phrase. At which point I will cheerfully point out that "epistemic" is not a word I'm comfortable using in a sentence so I'll be on my merry way.