There are times when speech calls for nuance, and there are times when nuance actually hurts the points one is trying to make. More often, however, the former is what is needed, and without it, a person's words will cause them to lose respect and credibility. Baruch Horowitz has an excellent letter making this point (among others) at Mishmar that is being sent to Mishpacha magazine in response to the letter attacking R' Yaakov Horowitz*. Check it out.
UPDATE: DovBear & Harry Maryles both chime in as well.
* I don't believe the two Horowitzes are related.