"The role of the editor, as I interpret it, with regard to reviews (particularly academic books) is to look for reviewers who have a knowledge of the subject matter, or who will bring their own experiences or expertise to bear on the subject of the book. Once commissioned, it is not the role of the editor to reject reviews on the basis that they are uncomplimentary to the item in question."
That might seem reasonable at first glance, BUT supposing[ A hypothetical example] the editor has given the job of reviewing to someone who is biased against the AUTHOR on personal grounds or because they are a potential rival in the same field of work.
I am not saying this is the case on this occasion, I am talking about a hypothetical example, is it not the Editors duty to ensure that the reviewer is truly independent and is judging the book purely on its merits.