I actually think this is a symptom of something healthy: high density of information per word. As a recursive example: Let's say I agree with your post - as in

I actually think this is a symptom of something healthy: high density of information per word. As a recursive example: Let's say I agree with your post - as in, I think "you're right, posts are negative and I would also like to know why" - what should I post? I believe the correct answer is nothing. Nobody wants to read the same opinion in two comments - that's bad etiquette on a site with upvote arrows. On the other hand, let's imagine I disagree with your post. For example, if I think that the ratio of negativity to positivity represents the diversity of ways you can disagree and the paucity of ways to agree. What should I do? Well, I think the right thing is to post saying so, and to justify my disagreement in as much detail as I can. One opinion, one comment. As a consequence, I comment negatively much more than positively. Generally when I have only nice things to say I upvote and move on. Is that bad? Like you, I'm not sure, but I believe it emerges from good.