Great point 8ren, and perhaps this is a solution to the issue. A concern is that the mean-spirited comments are not always countered in a thoughtful manner, or in time before the post drops off the front page. That said, perhaps we can draw on your suggestion, and as a community be more vigilant in quickly responding to mean-sprited comments in a logical and dispassionate manner to counter their effect.
I'm highly supportive of thoughtful debate, but my impression is that some of the up-voted comments lately have crossed the line from debate to ridicule.
I would rather not single out any individuals/comments. In any event, it appears like a growing issue across the community, and is not isolated to just one or two people.
If mean-spirited comments are down-voted, then it's not much of an issue. The problem is that I've started seeing mean-spirited comments receiving up-votes, and rising to the top of discussions. How do we solve this as a community?