Skeptics tend to react like that, so it's not very surprising that LW teaches it. What seems insufferable about it to me is that it's unfair. (I disagree with explanations like "it's an attack on your identity".) I'm fine with people who refuse to talk about a topic. I'm fine with people who say "I believe this, and I don't want to argue about it now", and don't start arguing when you state disagreement. But what these people are doing is making assertions, and sometimes arguments, then dodging. If you're not willing to discuss something, don't start discussing it. In part it's a status grab ("I'm allowed to assert things, you aren't") but mostly it's the sheer stupidity of "first expressed idea wins".