To me, the rude thing is to be intentionally insulting or intentionally patronizing. The cause being championed in the act of being rude is entirely irrelevant -- it's just a rationalization for rude behavior, and nothing more.

And I say that without finger pointing, nor without any intent of saying I'm perfect about this. I'm sure most regulars know that I recently had a bad day, and was in fact insulting to someone on these boards who hit a pet peeve of mine.

None of us is perfect, but we should avoid being rude ... and when it's brought to our attention that we were rude, we should both own up to it, and apologize for it. Signal-to-noise ratios, and perceived laziness, are not excuses for being rude to people.