[ska]

What is puzzling to me is the idea that being rude contributes anything to the cause of maintaining a sound architecture.

As far as I can see, if you have to say "no" doing so politely has no downside, whereas behaving like this clearly has some.

[R0b0t1]

Some people don't "get it" unless you at least try to appear rude. It's possible to waste a lot of time by not properly telling people off.

[ska]

In my experience being clear is always enough here, being rude is not needed.