If posting a non-consensus view tends to result in a negative or 0 karma, and posting a consensus view tends to result in positive karma, then it is likely that people are going to post consensus views much more often than non-consensus views.
I likewise object to those who mindlessly downvote or upvote. On my part I think nonsensical upvotes are worse than nonsensical downvotes, though, as it causes karma inflation. There exist people who'll upvote people just for saying "Hi", and I'm guessing they upvote every other comment they see. This rewards quantity instead of quality -- which serves to reduce quality.
Without having a wide range of views to moderate opinion, consensus becomes like a runaway train becoming progressively more one-sided.
This is largely what the article on Evaporative cooling of group beliefs is about. But I don't know how to fix this perceived problem, except to encourage you to speak and post about those non-consensus positions.
Eliezer once told me:
If there's one rationality skill I like to think I'm pretty good at, it's this one: the skill of saying "Oops."
In fact, I say "Oops, fixed, thanks" so often on Less Wrong I once suggested I should have a shortcut for it: "OFT."
And I don't just say "oops" for typos and mistakes in tone, but also for mistakes in my facts and arguments.
It's not that I say "oops" every time I'm challenged at length, either. I don't say "oops" until I actually think I was significantly wrong; otherwise, I stand my ground and ask for better counter-arguments.
But I'm sure I can improve.
Wanna help me debug my own mind?
Tell me: On which issues do you think I most obviously still need to say "Oops"?