In Part One (I haven't read all 3 parts) Morris examines statements people made about the photographs, and why - how - they came to those conclusions. He remarks on a passage in a book by Ulrich Keller, in which he states that "x is obviously h because...." To my liking, Morris takes issue with the evidentiary basis for these claim being that they are "obvious."
As I’ve said elsewhere: Nothing is so obvious that it’s obvious. When someone says that something is obvious, it seems almost certain that it is anything but obvious – even to them. The use of the word “obvious” indicates the absence of a logical argument – an attempt to convince the reader by asserting the truth of something by saying it a little louder.