Not sure this really obvious analysis really helps. I've seen a lot of people thinking they are really smart for saying that everyone including them are idiots. Adams made a lot of declarations or actions that shows that he really thought of himself as "able to see what the idiot sheeple were not able to see", and this quote is not out of character at all: "you idiots don't even realise that everyone is an idiot including me".
I think The Relativity of Wrong (Asimov, https://hermiene.net/essays-trans/relativity_of_wrong.html) is a nice counterpoint to this. Sure, we may say everyone is an idiot in some area. But there are relative levels of idiocy, and there are basic tasks you can sort of master. At the very least you can minimize your own idiocy if never eliminate it. I think mastering most essential areas in life can make you unworthy of the title of 'idiot', at least not overwhelmingly so.
There are infinitely many things to know, but not all of them are important. Knowing finitely many things (which is all we can do) can still keep us alive and well, at least for a while. And we can know some of those finitely many things increasingly well, if never perfectly.
Just as an example, if you manage say your personal finances pretty well, your health pretty well, perform any civic duties you might have, maybe do some social good or social work or charity etc., if your relationships are reasonably agreeable, respectful and pleasant, etc. and if you have a good amount of joy or peace or satisfaction, etc. in your life, then I wouldn't call you an idiot. This is not an impossible ask to know infinitely many things or infinitely precisely.
And we can learn it over 30 or 40 years, or more, prioritizing the most essential first.
Moreover, I'd say whether you can be called an idiot is context-dependent. If you get a typical (non-idiot) person, and put him in a highly specific job (which he isn't qualified for), say manager of inspectors of nuclear power plants, then he might behave like an idiot; in this case the best ability is probably the meta-ability to recognize one's own limitations and refuse work you're not qualified enough for.
Like, any person (literally any person) can theoretically be put in a situation that he might do significant harm or something stupid, this just means we have to work in contexts and understand and do well within said context; we could only legitimately be called idiots while failing badly or unethically within a canonical chosen context.
I really just don't think it's generally a good idea to go around calling ourselves (or anyone else) idiots. Too broad, derogatory, and tries to put an irremovable label on a person, which as I've explained, almost never deserves such an absolute classification.
My point was not that doing something stupid means someone is stupid, but that the examples I've provided are showing that Adams was prone to think of himself as smart when he was not. So far, there is no much proof that Adams was particularly smart (unless you are arguing that everyone can be called smart)
> Not sure this really obvious analysis really helps
Doesn't help you, sure. I'm not a fan, as a matter of taste and am self-aware enough to recognize it. The near-reliable output of his creativity and the pervasive notions, distilled and distributed to the culture are proof enough for history.
