Like what? Give me something that's true, "counter-productive", and relevant to LW.

"I greatly hate your post because it makes me irrationally infer things about your nature despite my knowledge of relevant biases, which makes me hate your post and you even more, which is irrational. Now let's all discuss this because I don't want to make the effort to go read up and train myself to become stronger."

...seems like a decent enough fictive example. It's true (within the context of the thought experiment), it's directly relevant to LW (it's about the user's rationality), and starting a large discussion about it is very counter-productive since the user in question should just read and practice rationality skills, as that would be much more efficient and productive, and the discussion might slow down other people trying to improve themselves and generate lots of noise.