Really? Honesty can be brutal?
It is my experience that those who endorse brutal honesty are hoping we'll all become just as rude as they are, so they don't stand out so much. After all, why should they have to learn manners just to fit in with all of us, what, gently honest people?
Honesty is not brutal. Honesty might be direct, it might even be painful. But pain is about the perception of the recipient, not the intent of the speaker. Some truths do indeed cause pain, which is why some truths change lives.
Brutality might also change lives, but there's probably a bigger market for truth.