As long as we're going meta here, I am thinking it would be more accurate statement would be that policy discussion posts tend to attract hundreds of comments. Policy discussions are the bike shedding topics of forums like this one. Everyone can participate because they require only an opinion and the barrier to having direct experience is low.

I don't believe it is a bad thing, rather it is the fact that a lot of people reading HN really want to participate in the discussions, but feel they don't have any direct experience so no clear way to participate. Comments like "I agree" do get down voted heavily, and even clever humor. So what does that leave? It leaves topics like gender discrimination or workplace drama.

I've seen similar participation in Ask HN type topics as they again often solicit opinions on a common issue.