I remember when an author stuck her foot in her mouth. Hundreds of people wrote reviews who never even read a sample attacking her book. This has been going on for a long time. *sigh*
The reviews on Amazon specially KDP books are usually fake to begin with. Authors get their family, friends and other authors or people from Facebook or Twitter. Some promise a free book in return for a favorable review.
I have read several books that got negative reviews that I've really enjoyed. I had to wonder who the author ticked off? I've also read several books with tons of good reviews only to find the book was mediocre at best.
It isn't just books. It happens with music too.