How accurate does this judgment seem to your own knowledge of Mount Stupid, and further, what tools other than having your gross ignorance exposed have led you downhill toward expertise and humility?
I mostly agree with your analysis above; I would add, however, one very internal factor. People who do not possess significant expertise in a complex area almost always tend to underestimate the complexity of all complex systems. Even if they read on complexity, they rarely get an intuitive feel for it. So, reading a few popular books doesn't just introduce the problems you have stated above. Since there is no intuitive understanding just how complicated things are, a person feels that the few information they have gleaned are sufficient to make an informed opinion on a topic. IMHO, this general problem also stands behind the popularity of many simplistic (and ultimately destructive) ideologies based on simplistic approaches to complex systems (such as, say, communism or libertarianism).
Along those lines, a thing that helped me a lot in this regard was becoming an expert in a complex field. Seeing how very intelligent people form deeply wrong opinions about things I understand made me very, very aware of similar biases in my thinking about other fields. It didn't cure me from forming such opinions, but it does force me to reexamine them aggressively as soon as I realize their existence within my mind.
A little knowledge is a dangerous thing, not sure what the official name for this particular cognitive bias is (feel free to enlighten me). Probably most of us can recognize that feeling of enlightenment after learning a bit of something new and exciting, and not realizing yet how far it is from the mastery of the subject. I suspect that learning the LW brand of rationality is one of those. (Incidentally, if the words "LW brand of rationality" irked you, because you think that there is only one true rationality, consider how close you might be to that particular summit of Mt. Stupid.) See also the last bullet point in the linked comic strip.
As an exercise in rationality, I suggest people post personal accounts of successfully traversing Mt.Stupid, or maybe getting stuck there forever, never to be heard from again. Did you find any of the techniques described in the sequences useful to overcome this bias, beyond the obvious of continuing to learn more about the topic in question? Did you manage to avoid turning Mt.Stupid into the Loggerhead range?
My example: I thought I was great at programming fresh out of college, and ready to dispense my newly found wisdom. Boy, oh boy, was I ever wrong. And then it happened again when I learned some more of the subject on the job...