People "on the spectrum" are not great communicators, and also struggle to understand what it is other people know and don't know.
Also, documenting is genuinely hard, even if you don't consider that it changes all the time. Which it typically does.
Not that I disagree -- working in highly technical fields this long, I could categorize 80% of my co-workers as lacking typical social and communication skills and you never know the real reason. It's to the point where I see women get promoted to management roles more often because they're superior communicators.