How do we know how good the supporting evidence is if we have no way to assay it for ourselves? At that point, aren't we just forced to take poster's word for it? That's not even as good as evaluating their performance because it's completely results independent. A lot of the time, logical fallacies just come up as an excuse for the poster to say whatever they want without having to back it up.

Assuming that we could see how people implement their own theories, we would have a feedback loop; however, many theories inside less wrong operate inside a vacum. We used to depend on logic to evaluate theories, then we stopped and moved into the scientific method, because pure logic doesn't work outside of a closed environment. It only works when you have a solid grasp of the intial variables.

That's rationalizing groupthink. IMO you should speak the truth as best you can, and change your estimated truth based on the arguments you read and the evidence presented, not on guesses about what your audience is willing to listen to.

From your complaint it sounds like they're forcing you to march in lockstep with everyone while chanting slogans; compared to being asked to back up your assertions.

Call it what you will, they believe it has a positive correlation with group success, so I approve of them pursuing such a course of action.