Sorry, this is where I am completely in disagreement. I believe that people who are rude need to be shown that being rude will get you slapped and after enough slaps they will start to catch on that it isn't helping them at all. Typically ignoring rude people entitles and empowers them more and in duty finder situations I've seen rude people completely control the party because no one was saying anything back to the person. I've seen innocent people kicked from parties cuz people were 'following' the rude person because no one bothered to challenge this guy's behavior.
Someone has to stand up to them and show them that they can't just bully everyone into submission and if that makes me 'rude' too then so be it because at least I'm trying to deal with these people.