I don't really buy the theory of this all being due to the education systems of Western culture. In my 20 years of education there was very little emphasis on c

I don't really buy the theory of this all being due to the education systems of Western culture. In my 20 years of education there was very little emphasis on challenging ideas or proving them wrong. I'm almost tempted to say that there was absolutely none. But as you can see from this very message, I'm totally happy to write a knee-jerk negative reply. What I believe is really happening is that it's hard for a yes-man to add any value to the conversation. "What great points you have! Totally agree! +1" is going to be just noise. It takes a large amount of effort to simultaneously agree and add something to the original article. In contrast it's very easy to add value by pointing out any parts that are actually wrong, or by highlighting areas of disagreement since that's likely where the meat of the issue lies. (Of course there's going to be a threshold at which the value of pointing out errors is lower than the cost of the reply aggregated across all readers, such as pointing out insignificant typos or grammar mistakes). Finally, I strongly disagree with this: "But pointing out all the places other people are wrong rarely teaches us anything". It probably doesn't teach anything to the person who disagrees, since they hopefully are already familiar with whatever issue they're disagree with. But it does teach something to others. And a place where people go to learn but nobody teaches sounds pretty miserable.