So the hypothesis is that if a group of people have a belief because of the absurdity heuristic rather than the evidence, if you show them one piece of evidence that goes against their belief they'll rationalize something like "but what about all the other evidence?"
But if a group of people have a belief because of the evidence, and you show them one piece of evidence that goes against their belief, won't they also say "but what about all the other evidence?"
This is problematic, since it means that "confronting" people is a bad way to get information about them, even to give them information about themselves. Rather than zigging or zagging, try zogging. What sort of tests can you think of that differentiate well between people who are thoroughly biased and people who used evidence?
People who go back and downvote every post or comment a Less Wrong user has ever made, please, stop doing that. It's a clever way to pull information cascades in your direction but it is clearly an abuse of the content filtering system. It's also highly dishonorable. If you truly must use such tactics then downvoting a few of your enemy's top level posts is much less evil; your enemy loses the karma and takes the hint without your severely biasing the public perception of Less Wrong's discourse.
(I just lost over 200 karma in a few minutes and that'll probably continue for awhile. This happens to me every few weeks. Edit: I mean it's been happening every few weeks for a few months for a total of only three or four. Between 400 and 700 karma lost total I think? I don't mean to overstate the problem.)