I have seen an increase in rudeness on this site over the last year. I have also seen an increase in short-fuse reactions to rudeness -- things that would have just been flagged and otherwise ignored in the past are more likely to garner responses, which garner responses, which turn into prolonged arguments with declining civility, sometimes with established sparring partners. And I think, though I'm not sure, that I'm seeing more claims of rudeness where I'm having trouble seeing what's rude about that.
(You want to know why we nuke comments more than some of y'all would like? Because when we see that sort of thing developing, we know how it ends and we really don't need to see it for the 50th or 100th or 1000th time. I can count on the fingers of one hand the number of times, in 4.5 years, one of those comment death-spirals has ended with "gosh, you're right; I'm sorry and I'll fix that".)
We have more rudeness and also more willingness to be offended than we used to have. We need to do better, on both. It's draining on the community and, quite frankly, it's draining on the mods, most of whom have quietly taken extended vacations from the site at some point.
Moderators delete a lot of rude and non-constructive comments, almost always in response to flags. (It's a big site; ain't nobody got time to find and review every single comment or even, sometimes, every single post.) We have recently gotten some better tools that help us get a handle on patterns at the individual-user level, but broader patterns are harder to spot.
We've suspended users for rudeness. I anticipate that we will need to suspend more. It can be hard to judge when the threshold has been crossed, and perhaps we err too much on the side of leniency. A lot of the rudeness I see is borderline at the level of the individual comment, but it can be like Chinese water torture -- aggregate effects matter too.
So, some advice for everybody:
Reread your words before you post. Especially if you're writing about something sensitive or you're already worked up, try really hard to read your words from the perspective of someone who disagrees with you. Even if you think that guy is an idiot. Especially if you think that guy is an idiot.
Give the benefit of the doubt when reading stuff from other people. Especially people you disagree with. And remember that disagreement or constructive criticism is not automatically rude.
Watch out for accusatory language. Understand the difference between "you need to back that up" and "could you edit in some sources?" and between "that's nonsense" and "I don't understand". Understand that words like "troll(ing)" pretty much always make things worse, and name-calling is a violation of the Be Nice policy.
If somebody seems to be upset with you, take that at face value. That doesn't mean he's right to be upset with you, but it does mean that the two of you are already at reduced ability to communicate constructively.
If that happens to you a lot, work even harder on the other points in this list.
De-escalate. If somebody responds to you in a hostile-seeming way, don't make it worse. If that means walking away, walk away. Neither of you has a "right" to the last word. If you think you can get things back on track without raising the heat level (and want to), try that.
Your cultural background, mental state, or concern about certain issues is not an excuse to behave badly. Be less ready to make excuses and more ready to make amends.
Flag.
Read your flag responses! We can't respond to flags on comments, but we can and do respond to flags on posts. If you have a question about a flag response, ask. (If a comment flag is declined but the comment is gone, then we might have goofed (it happens) or we might be telling you that a "rude" flag was overkill but, nonetheless, it should go.)