It is a very subtle tale, indicating how deferring to authority can lead to lies and hypocrisy, along with a sense that that behaviour is somehow appropriate. It is also about cowardice - no-one daring to point out the obvious; it takes the naivety of a child in the story.
He's right. However he initially minimized a related theme which he later came to appreciate: First things first. We have to establish that a thing exists before we can study it.
Well, unless we write fan fic.
Fan fiction is an exploration of the play space available within an imagined world established by some prior literary work. It's not easy and it would be unfair to say that a fan fiction writer just makes stuff up.*
Several months of study may be required to master the constraints of some literary universe. Characters can't simply do as you please. They have strengths, weaknesses, alliances, enmities, and motivations. Any potential plot line is constrained by setting, materials, and the laws of physics. If magic is introduced, its uses and limits must be explained to the reader.
Imagine all the research necessary to write a good Star Trek episode. Without careful scholarship, distracting discontinuities and contradictions with what has gone before are bound to appear.
Theologians get annoyed when atheists accuse them of studying a non-subject. Anything that takes work isn't "nothing" ...
*Example of the upset that can be provoked when one fails to appreciate all the hard work and discipline of good fan fic. The first response is civil:
Steve Zara's last comment, in which he says that "religion just makes stuff up" is so ridiculously silly one could almost imagine that he really doesn't believe it. Has he read any of the 111 comments so far, and by reading I mean thoughtfully considered each word and phrase, pondered what is being said, how it is being said, etc.? It would seem not.