I found the book amusing, fun, if not a little campy. I had my mother read it so she could understand that what I do isn't "as crazy" as it looks. (she couldn't believe the physical and psychological "torture" depicted in the book).
I'm very sure it would have much more boring if he didn't use the artistic license he did.
I find it interesting that almost all people that are offended by book the study Yoshinkan (or an offshoot). Come on lighten up, have a thicker skin, and don't get riled up over the remarks of a person who just wanted to survive the course, then write half-fiction about it
All the Best,