I was going to put this in an open thread, but decided to make it a diary instead, as I believe it's important enough to bear repeating.
As with matters of race, or other issues that generate heat, controversy and large difference of opinion, I think what Armando said should be the norm at Daily Kos, and noncompliance disfavored as a point of departure. His approach:
First, there were some aggressive challenges to certain language used in some of the comments. While the substance of the challenges will be permitted in the group, the MANNER in which the substance of the challenges was presented will not be. If you have questions or concerns about certain rhetoric, you will have to put those to the other person in the most civil and courteous manner possible. No aggressive challenges will be permitted.
Second, when presented with these aggressive challenges, the persons challenged responded in a belligerent and aggressive manner. This too will not be permitted. You can choose not to respond, or, preferably, respond in a civil and courteous manner EVEN IF you were not treated civilly or respectfully. You will leave the moderation to me and/or to other moderators I will choose.
In other words, the burden of civility is on the reply and then again on the recipient.
The main drawback to this place is that discussion too often becomes an exercise of insults, often to the exclusion of diary substance.
To me it means one need not be polite in the substance of what they say, but in the manner in which they say it. The way I see it, if one attended a seminar where people engaged in similar discussions, where there is disagreement all the time, there would not be any mockery or the like. One who is disrespectful would quickly acquire disfavor and lose ability to persuade.
Liberals should behave with tolerance, not the opposite, and in a way that fosters, not hinders, communication and learning.