Most of the people I work with (professionally and personally) are perpetually self-critical despite being very intelligent and more than capable. The humility comes from growth over time and being able to remember doing work they'd consider terribly flawed today. If you're working with arrogant people, they're probably not growing and it'll make it harder for you to as well.
> people are inspired to come up with good ideas to ward off bad ones.
Interesting theory, but I think something else is happening here.
If you have a bunch of people trying to solve a problem, the game is implicitly defined as "propose the best solution." After the first proposal, the game changes to "improve on the best solution so far."
This is something to keep in mind during interviews [1] for people on both sides of the table. If a candidate is silent for too long, propose a bad idea and ask them to improve on it. That gets them talking out loud, and you get more info to go on. If you're a candidate, you can start with a bad (yet probably obvious) solution and explain why it's bad. In the process of talking it through, you'll likely think of a better solution.
[1] The algorithm/coding one-big-question-over-45-minutes style of interviews commonly conducted by large software companies.
It's interesting to me that all of your examples are also very important aspects of being an excellent Dungeon Master. I never made this connection between teaching and DM'ing before.
From the discussion here, I conclude this quote is widely accepted among those who provide quality discourse: "I try to comment when I have useful, unique, original, or non-standard things to say." This represents a desire to deliver a certain promised value. When you post on a forum, (or send an email, for that matter) you are making an implicit claim: is worth the audience's time to read your post.
For users like me, there is friction in posting because I have to convince myself that I've satisfied the implicit claim. For others, I assume, this friction is absent. So add it artificially: somehow make the claim explicit.
Maybe require posters to select from a list of categories (e.g. Useful Information, Insightful, Civil Disagreement, ...), explicitly claiming their post meets that criteria. Or, less restrictive: a required checkbox that simply reminds you of the claim you're making with your post.
I won't defend the author; my opinions here fall mostly inline with your own. But I still wonder if there isn't something deeper...
Presenting something as fact is an extremely quick way to find out if you're wrong. It's much faster than asking a question. The impulse to correct is stronger than the one to answer. So I interpret the post as the blogger's subconscious attempt at verifying and normalizing his opinions.
In this way, a blog is mostly a self development tool. I should start one of my own, I think. I never have before because I lack the hubris to think that my little discoveries are novel enough that anyone else would care. But I see now, maybe that's not the point.
In this video [1], he explains what happened "somewhere along the way". TL;DW: He failed at being a successful comic by telling the same jokes for 15 years, then got inspired by and emulated George Carlin, threw everything away and started over.
His story is not only inspiring, it transcends comedy. The idea that a mixed but passionate reaction is better than a lukewarm one applies to startups as well as entertainment.