I have reviewed both authors, and have not been shut down.
Recently?
Amazon has been clamping down on reviews to only those who have bought the book as they were getting heat about having a lot of “reviews” up for a product that were not from actual users/purchasers. I personally applaud them for doing so, if they are moving to squelch certain authors or subjects then they are shooting themselves in the foot with both hands, but they do have the capital to do stupid things