That's exactly the details to be dropped. Don't get hung up on how the article started with "natural speech", that's the bathwater. The baby is promote simple sentence structures and word choices that convey the problem and solution concisely without fancy complexity of language that doesn't add to understanding.
I really dont think the article is good at promoting that idea. And one problem (frequent with Paul Graham writing) is that it builds false dichotomy in between supposedly simple talk language and complicated written language.
Written language is not inherently more convoluted and complex. Not even on discussion forums with untrained people who dont read after themselves.
> It seems to be hard for most people to write in spoken language.
The written texts end up convoluted frequently because people do write them as they think they would speak. People speak in complex sentences, tone of voice making the difference. Then they see all the horrible warts and try to fix them - badly.
Also, the article does not contain actionable advice on how to write. It does not help you to deal with sentence structure nor help you to refactor bad sentence. It is fluff.
> I really dont think the article is good at promoting that idea.
It isn't. That's why I was pointing out that there's still some value here if you focus on it and not the presentation and all the parts of it you disagree with or otherwise dislike.