As soon as you click on User Reviews, they show two reviews (one good, one bad) next to each other. For whatever reason there are only a few bad reviews right now, but they are there to see. So the one negative review you desire is right there to see.

I notice Hubbard's latest book has only 3 reviews, a 1 star, a 4 star and a 5 star.

I haven't been monitoring Amazon's editing of reviews of anything, as I don't have the time for that type of activity. However, I use the reviews. If they were censoring negatives, why not get rid of all of them?