The community values articulate cleverness, and sometimes folks optimize for this by trying to be more clever than the author of the article under discussion.
The easiest way to move community norms is to write the comments you want to see on the site. (I'm trying to be better at this myself.)
You know skepticism is a good thing, but too much of it makes people reluctant to learn and even share things. I just think that an argument is something no one wins. [edit: as arethuza pointed out what I am truly against is cynicism i.e. crab behavior. I know you're wrong because I know what's right and you can't be right because I know I am right. That is exactly the sort of thing that the world doesn't need]
So, whenever I think someone is wrong instead of just screaming it out on them like I used to and sometimes still do. I try to be nice and genuinely listen to what they have to say. If I realize that I'm indeed right I try to gently nudge the idea into their minds.
I am not that good at it right now, since old habits die hard, but someday...
The easiest way to move community norms is to write the comments you want to see on the site. (I'm trying to be better at this myself.)