For the most part this doesn't happen, but sometimes, particularly if it's a hot button subject like politics or religion, it can bring out the worst in people's passions.
I work to keep conversations as civil as possible, knowing that sometimes we disagree. I'd rather have someone who disagrees with a hub or question etc. state in dignified fashion why they disagree. After all, many types of opinions exist and it's nice to consider others views. What I don't tolerate is sarcasm and being mean. We can make points without being condescending.
I will admit I've made responses a couple of times that others took as "rude" - simply because I disagreed. for example one was a response I made to a blanket statement that said atheists are not moral people are more or less to blame for societies problems and we need to have prayer in school again. I told the poster that her answer is insulting to atheists as a whole (because it is!) and she took that as rude and promptly took apart one of my hubs and twisted my words around... This is where things cross the line.
Yes you can disagree - and disagreeing is not insulting. We don't have to candy coat everything we say, but we can disagree in ways that respect other people. My thought on this particular exchange was that this lady had no right to insult an entire group of people and blame things on them, it was unfair and thus insulting - her response was that since I said her statement was insulting - that I somehow meant she was a bad person.
Keep in mind, we are also reading responses here. Sometimes things get misinterpreted also. I try to keep that in mind when reading anything here - so as not to overreact to an unintended slight.
With those who are blatantly rude, I delete their answers and comments - no need to keep them around, it isn't going to teach them anything. I don't want nasty comments to degrade a good hub or conversation or answers so I delete and move on with my life :)
My biggest pet peeve is the passive aggressive thumbing down of answers people simply don't agree with! That happens ALL the time and is very annoying. If an answer contributes to the question it doesn't deserve a thumbs down, unless it is rude, spammy, or off topic.