If you go further, the whole thing wraps around. His suppression of his own sexuality, led him to embellish, to write out his own internal dialogue into the "nonfiction" books he wrote. So it all eventually comes back to the thesis, but yes, it's a huge drag to read through, but then Sacks' own writing is so turgid and overly dramatic, like he was writing for an audience.

The first sentence too is apt, "butter colored suit that reminded him of the sun" is a great example of Sacks' writing style.