This is known as Cunningham's Law. Another example.The explanation (non-competitive vs. competitive mindsets, the latter of which is more motivating to act) seems quite convincing. In addition, could there also be an analogy to loss aversion (a tendency to prefer avoiding losses to acquiring gains)? Would people feel more urgency to correct what they see as wrong (and thus challenging what they see as correct) rather than explain what is right ("less wrong" vs. "more right", if we are not trying to avoid puns)?