In a literal sense, I agree with almost everything you wrote. He does not want to directly make the claim that he believes affirmations are magically affecting reality. He aims the text at people predisposed to certain types of woo. And he wants to convince those people to try his other type of woo. He doesn't say what he himself actually believes.

Where I differ from you in my take on this is that I also weigh what isn't there. He doesn't provide any form of alternate explanation. Nowhere does he say anything that comes close to "I don't believe that affirmations work this way" or anything of the like. I also don't agree that his hedges clarify anything, rather they muddy the waters.

He presents a thesis, presents other people's arguments for that thesis, presents no arguments against, and then explains that he lives his life in a way consistent with believing in that thesis. The hedges fill one function: to make it harder to argue against him. If the arguments aren't his, the chapter stands even if the arguments fall.

To me, that is basically arguing for the thesis, but in a roundabout and quite defensive way. What other point would you say that that chapter conveys?