Does a "hacker type" correlate strongly with a certain race, gender or nationality? Is one political point of view more valid for "hacker types" than another? The guidelines of the actual site uses the qualifier "a good hacker," implying one should not only be a hacker, but "good" Good at what? Programming, startups, or conforming to an archetype of a "hacker" personality?
Even "intellectual stimulation" tends to lead to the belief that only intellects of a certain type should be considered valid. Dang has to constantly correct people who assume that content which is intellectually stimulating, but not explicitly about startups or technology, is off topic or detrimental. Hacker News is not what some people assume it is. The "good hacker" archetype itself is the problem, as people differ wildly as to their interpretations of it, and by extension, in their belief in what the true theme and purpose of Hacker News is.
Yet what really separates the average Hacker News user from the average Reddit user? I don't know how many users HN has, but Reddit has tens if not hundreds of millions, so one can assume the average Reddit user is not necessarily less intelligent than HN. Reddit also has a number of high quality subreddits which are heavily moderated and used by experts in their field, so I'm not certain HN possesses more technical acumen than Reddit, either. Quality of articles? Many things posted here also appear on Reddit.
Why, then, do Hacker News users seem to detest Reddit so much? Because among the few commonalities in the various interpretations of the hacker archetype are elitism and a distaste for mainstream culture, and new users want to appear to be "good hackers" and hating the mainstream is what people think "good hackers" do. Yet read the comments here, especially in controversial, non-technical threads where posturing as a "good hacker" has less value. Most are no better than, or even worse than, comments in similar subthreads on Reddit.