Earlier quoted context omitted.
Ah the old nerd trick of disregarding the context of a statement and applying it to a context where it clearly doesn't work. Do you really think Paul Graham is arguing against James Joyce style writing? Why would you think that?
Because James Joyce's style isn't "simple" by any stretch of the imagination, I would guess? And the essay presents its position as a general statement void of all context. What context are we supposed to assume here?
Are you sure? From the blog (first sentence):
> I try to write using ordinary words and simple sentences.
Since the "I" in this case refers to someone who does not write poetry, speculative fiction, drama, tragedies, comedies ... and only ever writes for a technical audience, the context is clear: technical[1] audience not seeking poetry, fiction, drama, etc...
Further one he says:
> So you can't assume that writing about a difficult topic means you can safely use difficult words.
Once again, that indicates to me he is talking about writing something technical[2], not prose or poetry.
[1][2] "Technical" is not limited to IT and engineering; it's about anything that involves technique. Describing dance moves is "technical", as is writing a recipe (which is very similar in technique to writing a tiny program) or anything involving writing down music (Should you use 7/4 for the first verse, or alternate between 3/4 and 4/4? Which will be clearer to the flautist?)