Like in this thread, we can note the irony (and worshiping) of the community, with the top comment (11 points so far) done by anewaccountname, deliberately taking a piss out of PG's essay.
The fact that people here upmod/downmod based on whether they agree rather than whether it's insightful really bothers me. I think it's the wrong incentive structure.
If you want to downmod, it's no big deal. But there seems to be some proportion of the audience that feels vindicated in their views just because the opposite view was downmodded. Downmodding does not make opposing positions less legitimate.
These people seem to be different than the ones who write replies. I've had multiple lengthy threads where I hardly get any mods either way while discussing, and then when I wake up the next day I have -20 karma, but no new replies.
Likewise, it was funny that the "Funny..." comment was modded to -1. At least, I found it funny. Point being, I don't think these were rewards for groupthink, so much as rewards for geeks being clever.
I could go down a longer list: because mob rules is a not-so-good policy for quality reading material, because if one group votes on agreement and another group votes on quality then the agreement group "drowns out" the quality group, because it takes about 2 seconds to determine whether you agree with something, whereas determining if something is worth reading takes a lot longer (and is more valuable information), etc.
Note that I upmodded you, even though I take issue with your position. That's because you asked a good question. In another world, I'd just downmod you because I thought you were mistaken and for most readers the question would never have been asked (or answered)