If the core idea that was intended to be broadcasted to the world was a "contribution", and LLM simply expanded on it, then I would view LLMs simply a component in that broadcasting operation (just as the internet infrastructure would be), and the author's contribution would still be intact, and so should his enjoyment.

But his argument does not align with that. His argument is that he enjoys the act of writing itself. If he views his act of writing (regardless of the idea being transmitted) as his "contribution to world's knowledge", then I have to say I disagree - I don't think his writing is particularly interesting in and of itself. His ideas might be interesting (even if I disagree), but he obviously doesn't find the formation of ideas enjoyable enough.