The book has very harsh words for teachers who are incongruent:
“1. There were a number of extremely well-trained practitioners of NLP who were themselves clearly capable of miracles (relative to the capabilities of other systems of change work) with clients; however it apparently had never occurred to them (or perhaps they simply had chosen not) to apply the patterning to themselves—that is, self-application of the patterning. Thus, my perception was that many of them were incongruent in significant contexts in their lives—there were portions of their personal and professional lives that showed absolutely no presence of the choices they busily assisted others in creating in their lives. I was not happy with this situation.” (p. 231)
And later we find: “CAVEAT: Messengers incongruent with the message they purport to bear are not listened to, nor should they be!” (p. 366) Given the incongruencies that appear in this book, this statement becomes self-referential (violating the theory of logical types), paradoxically telling us not to listen to what it says!
I agree that self-application of the methods we teach is vitally important for all of us, and one result of this is congruence, a worthy goal. However over the last 67 years I have learned a great deal from people who were incongruent, and a degree of incongruence may be inevitable for us mere mortals. We are all still learning, and all of us have a long way to go.
Learning a new skill or understanding always results in incongruence, at least initially. So if someone were always congruent, that would mean that they could never learn anything new! I do agree that incongruence is an important signal that indicates an opportunity for further learning, change, development and discovery, and this book provides more such opportunities than most of us have time to pursue.