I absolutely believe that his Good Reads lists provides relevant insight into his psyche. It's incorrect to label his reading list as "irrelevant." IMO
Books, for many of us who love reading, aren't just mindless things. My book collection would tell you a lot about who I am. You'd know just by looking through my book shelf what I'm passionate about and the causes in which I support. It would give you an idea of some of the challenges I've faced in my life, as well as plenty of indicators of my ideologies, and clues on my chosen career path.
Readers of non-fiction care very deeply about the topics they read about. I'm an exclusive non-fiction reader, and each book I choose to read has meaning to me. The only fiction I buy would be considered part of the Canon of literature, which would actually tell you that I'm a bit of a literary snob or have an education in English literature. Both are true.