It's hysterical. Amazon has been letting this go on for some time. They have to know about it. Maybe they just figure that when people are done posting their sarcastic reviews, they can suggest other books and people might buy them. It brings traffic into the site, so they might just let it be. Wouldn't be surprised if they get enough complaints that they stop selling the books.
Sometimes I don't understand the logic behind anti-vaxers. I understand it under certain circumstances. I have a medical exemption from school vaccinations because I did go into anaphyaxis after one, so I only get the flu vaccine. It's a big production otherwise, so my doctors decided to just have me get an exemption and not run the risk. My cousin and his fiance decided not to vaccinate the baby because he's got the family history of allergies, kid is already allergic to latex, and he reacted badly to the HepB vaccine. They're not anti-vaccination; the girls are vaccinated, but she had a bad feeling about vaccinating the baby, especially after the doctor's office wanted to give him 7 vaccines (he's not even three months old) and she put her foot down. So they're holding off for now.
But just to not vaccinate your kids because of a minute possibility of something happening...I don't understand it. The ones who say that vaccines cause autism I'm rather insulted by. First of all, there's no merit to that whatsoever. And second, even if it were true, you would rather have your child die from complications from a disease that they might have been vaccinated for than live with autism? Is autism so undesirable that you would rather have your child die or suffer other complications? My brother has autism, but he's here, and that's what's important. They make it sound like it would be so horrible. It's not ideal, and I certainly would rather that he didn't have autism, but I kind of find it insulting.