That's a legitimate concern, but I don't think HN is quite that homogenous. I also don't think we tend to downvote out of disagreement, which would be required in order for groupthink to set in. You occasionally see a thoughtful comment expressing an unpopular sentiment get downvoted, but not often and usually not for long.
For groupthink to be a serious threat, it's not simply enough to have the top-rated posts express a given view, you also have to have contrarian views be buried. I don't think that a group of people that pg would be likely to pick would a) upvote all the same things, or b) downvote posts they disagree with. As the supervoter bit would be passed to people who voted in generally the same way as a reasonable number of the superusers, it would be unlikely that people who downvoted out of disagreement would get the bit. Further, I think there's a wide enough range of views amongst the people pg would likely select to minimize the likelihood of a single viewpoint gaining dominance.
There's enough contrarianism built into the basic personality of most HNers that I think we'd be fine.
I have unfortunately seen all the things you describe, for example see any thread about PHP, or the thread about perl and random syntax, or about using an ORM for SQL.
I've seen it in threads about social issues as well, although none come to mind right now.
I've seen it too, and while disturbing, I don't think it's representative of the HN population as a whole, and I certainly don't think it's representative of the types of people who would initially be picked. The goal of my proposal is to counteract the people who do engage in those unwanted behaviours by giving proportionally more voting power to those who demonstrate that they don't.
For groupthink to be a serious threat, it's not simply enough to have the top-rated posts express a given view, you also have to have contrarian views be buried. I don't think that a group of people that pg would be likely to pick would a) upvote all the same things, or b) downvote posts they disagree with. As the supervoter bit would be passed to people who voted in generally the same way as a reasonable number of the superusers, it would be unlikely that people who downvoted out of disagreement would get the bit. Further, I think there's a wide enough range of views amongst the people pg would likely select to minimize the likelihood of a single viewpoint gaining dominance.
There's enough contrarianism built into the basic personality of most HNers that I think we'd be fine.