He expands on this in his conversation with Bryan Garner (of Garner's Modern English Grammar) published as Quack this Way, and I think he gets to the core issue, which is that your ideas are not interesting to anyone but you; if you are showing off how smart you are, you are assuming the reader will find your ideas as important and interesting as you do. It is the writer's job to show the reader why they should be interested, why they should care.
Infinite Jest is a also a good example of something which goes against TFA's point, it opens with a very sterile, impersonal, literal and completely disconnected first person narrative, he gives us nothing to care about. But it evolves, but he still doesn't give us anything to care about, just has the narration turn in on itself despite it seeming to have nothing to turn in onto. All he really gives us is the suggestion that there is something more than what we can see. He gets us interested and curious but I don't think we really care at that point.