I agree with the author's observation. Geek culture is incredibly unforgiving, and proudly so. To some extent this might be just a part of hacker tradition, but I think there's a deeper problem - it isn't always easy to tell who the authority on a subject is in a random group discussing a highly technical issue.
Let's take the sports analogy the author used. It is immediately clear who is more apt at skateboarding and thus should be doling out advice. The power relation is clear and accepted on both sides, which allows for constructive instruction to take place.
Discussing things on HN, however is different. In general, technical discussions amongst people who don't generally know each other are a process of discovering the appropriate power relation. We are exchanging comments and trying to gauge who is more knowledgeable. If I were to try to teach someone before they've acknowledged I have something to teach them, I'll come across as arrogant and an unpleasant argument will likely begin.
I'm not sure what the answer is. Sometimes I'd like to see more humility in the communities we're referring to here, but I also don't want to read insecure, watered-down opinion. It would be the best of all worlds if people stated their case as strongly as possible, confident that everyone knows they're aware of the possibility or even overwhelming probability they're wrong. I think that would eliminate a lot of the pain and noise in discussions on forums such as this.