A lot of dojos preserve to some degree the social standards of Eastern countries where the sensei's sensei came from. And in Eastern countries, it's much less acceptable to try to question your teacher, or change things, or rock the boat, or show any form of weakness. I taught school in Japan for a while, and the first thing I learned was that naively asking "Any questions?" or "Any opinions on this?" or even "Anyone not understand?" was a waste of time.
Western cultures are a lot better at this, but not ideal. There's still pressure not to be the one person who asks all the questions all the time, and there's pressure not to say anything controversial out of the blue because you lose more status if you're wrong than you gain if you're right. I think part of the problem is that there really are dumb or egotistical people who, if given the chance will protest that they know a much better way to do everything and will waste the time of everyone else, and our society's decided to .make a devil's bargain to keep them under control.
The best solution to this is to found a new culture, live isolated from the rest of the world for a century developing different cultural norms, and then start the rationality dojo there. Of possible second-best solutions:
My Favorite Liar. Tell people that you're going to make X deliberately incorrect statements every training session and they've got to catch them.
Clickers. One of my lecturers uses these devices sort of like remote controls. You can input information into them and it gets sent wirelessly and anonymously to the lecturer's laptop. The theory is that if he says "Raise your hand if you don't understand this" or even "...if you disagree with this", no one will, but if he says "Enter whether or not you understand this into your clicker" he may get three or four "don't understand" responses. Anonymous suggestion boxes are a low-tech form of the same principle.
I always found the concept of Crocker's Rules very interesting. I also remember hearing of a community (wish I could remember which) in which it was absolutely forbidden to give negative feedback under certain circumstances, and the odd social dynamics that created. In a dojo-like setting, there might be situations when either of these two rules could be ritually enacted - for example, a special Crocker Hat, such that anyone wearing that hat was known to be under Crocker's Rules, and a special No Negative Feedback Hat (but with a flashier name, like White Crane Hat of Social Invincibility), which someone could wear when questioning the master or something and be absolutely immune to any criticism.
My Favorite Liar. Tell people that you're going to make X deliberately incorrect statements every training session and they've got to catch them.
I can think of only one example of someone who actually did this, and that was someone generally classed a a mystic.
Someone deserves a large hattip for this, but I'm having trouble remembering who; my records don't seem to show any email or OB comment which told me of this 12-page essay, "Epistemic Viciousness in the Martial Arts" by Gillian Russell. Maybe Anna Salamon?
It all generalizes amazingly. To summarize some of the key observations for how epistemic viciousness arises:
One thing that I remembered being in this essay, but, on a second reading, wasn't actually there, was the degeneration of martial arts after the decline of real fights—by which I mean, fights where people were really trying to hurt each other and someone occasionally got killed.
In those days, you had some idea of who the real masters were, and which school could defeat others.
And then things got all civilized. And so things went downhill to the point that we have videos on Youtube of supposed Nth-dan black belts being pounded into the ground by someone with real fighting experience.
I had one case of this bookmarked somewhere (but now I can't find the bookmark) that was really sad; it was a master of a school who was convinced he could use ki techniques. His students would actually fall over when he used ki attacks, a strange and remarkable and frightening case of self-hypnosis or something... and the master goes up against a skeptic and of course gets pounded completely into the floor. Feel free to comment this link if you know where it is.
Truly is it said that "how to not lose" is more broadly applicable information than "how to win". Every single one of these risk factors transfers straight over to any attempt to start a "rationality dojo". I put to you the question: What can be done about it?