The point being that rude isn't evil in itself although it may be inappropriate. The proper response to someone wanting to hold a klan meeting in your house is "get the hell out". Rudeness is a feedback mechanism.
The point being that while less than ideal it isn't unsuccessful in itself. Extremes are useful for extrapolation - even if it will never reach that point it is helpful to have the worst in mind to be vigilant of the flaws it may start to drift into.
> And rudeness can be very called for in response to evil.
You have constructed quite the strawman to argue against the myth, well done.