Not quite Dunning-Kruger which might have been a statistical mistake.
Disclosure: former maker.
I suspect it is because lower IQ people struggle to recognise higher IQ in others.
Smartest guy I know said the smartest guy he knew delivered pies. Smart people are cryptic.
Robocat's perverse corollary: when you look for smartness in people you can always find it: usually in an unfamiliar area.
I believe smartness is an ability to intuitively see patterns that others do not obviously see. Our writing is full of signals and some people are adept at reading a lot into a simple comment. I'm not suggesting I'm any good at it, and unfortunately there are also a lot of people who think they're good but are not.
Mentioning "IQ" at all is a huge flag: often used by people that are academically successful but that is a poor measure of how smart someone is.
While my comment was written in a cheeky style, I am actually writing about my own experience as a reasonably smart person dealing with my own lack of wisdom over the years.
Don't worry: I don't actually suspect you have a low IQ.
Yes, completely off-topic, I shouldn't bite I know!