Sometimes really good articles don't have lots of comments. In these circumstances, I post an "excellent article!" comment just to give the author some feedback that someone somewhere actually read the article, and they really liked it! Humans writing articles appreciate that.
I am denying importance of compliments but they lose their lustre if the whole culture of forum is to "appear too nice"; it just gives an impression of everyone making comments for the sake of it. Besides that, the entire point of a forum doesn't bode well if there aren't any strong comments touching the subject, even if they are cynical or scornful. Take a look at OP's example of the "Should you leave a bad job?" thread [1].
The first comment is surely harsh and questions the entire thought process of hating a mundane job. Some people would disagree with it; some would not but I would be disappointed if the comment didn't exist.
