Really think about how very much is wrong on the internet compared to your capacity to try to correct it. I think this might be a case of cultivating scope sensitivity.

Or (which is what I think I do) combine that with a sense that giving a little shove towards correctness is a public service, but it isn't a strong obligation. This tones the compulsion down to a very moderate hobby.

For me debating with people on LessWrong somehow cured the syndrome. Now when I see a political debate among non-LessWrongians, the participants seem like retarded people -- I no longer expect them to be reasonable; I don't even expect them to be able to understand logical arguments and process them correctly.; I don't feel any hope of conveying anything meaningful to any of them. (At best we could have an illusion of understanding.) Speaking with them would be like speaking with a rock; certainly not tempting.

I am not saying this is a correct model of the world. It is probably exaggerated a bit. Just explaining that this is how I feel, and this is what cured the syndrom.

These days the syndrom manifests mostly when speaking with someone whom I consider they could be rational. If they feel like a potential LW candidate. It usually ends with me revising my opinion about the candidate, and silently stopping.

So, for me the cure is feeling that the inferential distance between typical internet discussion and rational discussion is so huge that I don't have a chance to overcome it in one debate.

Cultivate a sense of warm satisfaction every time you avoid a pointless online debate.

I just became unwilling to devote the effort to replying.

Realize that it's not their fault, they are just automatons with faulty programming.