[vog]

> It reminds me of a friend that used to start off particularly rude statements by saying "I don't want to be rude but..."

I don't see the contradiction here.

I interpret these kind of phrases as: "I don't like to be rude, and normally I'm not, but in this case I need to make an exception."

Frankly, not everybody actually meant to say that, but this interpretation still helps to deal with those situations in a civil, non-escalating way.

[bryanrasmussen]

I suppose, although the normally I'm not would mean not hearing it so often that it becomes a well-known identifying personal tic.