Tech people are pretty smart, on average. It's a somewhat demanding professional career. There's a hell of a lot of difference between "smart" and "infallible".
Death to the halo effect https://en.wikipedia.org/wiki/Halo_effect
I understand that this is not a very high bar to set in comparison to other working professionals, but nearly everyone in the tech industry, and most other people who have a desk in a company's head office, are working at a level above the average person. Many of the posters on HN are biased by their personal and professional contacts and have an incorrect impression of what an IQ of 100 looks like, or how smart the average person is.
Going back to what I said originally, being smart is not the same as being infallible. Smart people can get themselves into all sorts of trouble that everyone else would have the humility and common sense to avoid.
Coding might imply a capacity to do other complex jobs, but not to become an expert in said field. There's only one way to do that, with time and effort.
My main problem with the original comment was that it implied tech people aren't actually smart, when they are usually well above average. The problem is confusing general intelligence with knowledge in specific areas, not that they're secretly stupid. I think this is close to what you're saying as well.
That's why Elon Musk got asked about COVID and Kayne about foreign policy. We need to stop doing that. Musk is great at building companies, knows nothing about virology. Kayne is a good at music, end of list.
If you're defining "dumb" as "below average for a programmer" then yeah that's... about half of us, turns out.
Programming isn't physics, but it is a profession that starts around +1 SD. Below that you're gonna wash out.
But that's drastically different than Engineering where calculations are done methodically.