That subject was formulated polemically on intention; but hear me out.
You are missing the very purpose of the book. The set of practices described is not just a list of dogmata. There is ample justification for each practice set forth, but no expectation that you will accept it; you are actively invited to disagree.
The point is, above all, to get you thinking. You are not meant to agree; you are simply meant to develop awareness for style and work on your taste.