I'm not saying that comments should be a circle jerk and, sometimes, on this site especially, they are.
What I'm saying is that people who play the game like that probably won't get very far, but they'll stop playing like that once they figure out it isn't working.
If a comment doesn't acctually hold any content, i'm not inclined to interact with it.
If I want to comment on it, if it's in a positive light, then I'll upvote it and I think that eventuelly most people will do the same.

No one has a genuine reaction to "Nice post"

Give people time to be real.