As I think about it, it gets to what's wrong with the idea of expecting to be friends, or to always get along congenially with co-workers, when in fact the reason for interaction in a business is to produce something of value.
No doubt this unpalatable person was impressively productive in both yours and OP's stories, and in a business environment, I wish that could weigh heavier than the difficult personality...
Don't think I have a point, but am genuinely curious why having a diagnosis for the behavior makes it easier to accept
It eliminates malicious intent. If you know they can't help it, you still might think it's not worth working with them. But you know that it's not personal.
What it doesn't do is justify the process drag introduced by designers who aren't domain experts or design for the sake of design.
So at the risk of having opinions that overreach the context I was given here, I'll argue that the materials were not "perfect", no matter how thorough.
In fact, I think it's possible to edit what you wrote a little and make the word "perfect" ironic. If someone is making colleagues emotional, that's a red flag that the approach to documentation leaves room for improvement, for instance. Good writing requires empathy for the audience.
I'm questioning the value of just shipping docs without following up that they meet their purpose(s). That's what I mean by empathy.
I can't imagine that approach working on any domain that isn't completely understood by the documenter - it simply leaves no room for learning.
And are you saying there were zero changes in requirements?
I - then working as a freelancer programmer for a few years - once had a (German company) customer where the person that I was supposed to work with was so unpopular and known as "difficult to work with" inside the company that the manager that had hired me for the job apologized profusely, especially that he had to place me in the same room with that person. All the people I had contact with were similar.
Why was he never fired? Well, because he was so good, you could say he was perfect. So they gave him a room for himself - usually it was about four people per office and accepted the rest. And I say that with decades of job experience in many software companies in the US and in Germany. The documents describing what he wanted down to the last detail were just.. perfect! I ended up doing two programming jobs for them a year apart and both times I simply took the documents and worked on it from top to bottom until it was done. I never had to ask a single question, there never were any changes. Sometimes I had to explain a few things I did, but that was just usual communication, there never was anything unclear.
And also, I never had any issues with that guy myself, even during the time we shared a room. He "merely" expected everybody to be on his level, other than that he was fine. Once a female colleague came into the room to ask him something, and in an exasperated tone he told her that he had already described everything she asked for in paper X in section Y. And he was right, what she had asked was right there. As always, he had everything perfectly planned and documented well in advance. Of course, that's no way to gain any social points and that woman was almost ready to cry (I had quite a few chats with people working in the other rooms and the women disliked him the most, but the men did too), but for better or worse, he was just too perfect and expected the same perfection from everybody.
That was the first and only time I ever had such an experience, everybody else apart from that one guy is just working normally. Right now I have the exact opposite experience, I program for people who only have very fuzzy ideas what they want. Works too - you just have to treat it differently and have a different mind set. That one job is one of my most memorable experiences, including the social drama.