Bit of a tangent, but I never understand why people say this. Don't they know that humor is one of the most potent weapons? If someone is offended, will they be less offended that they are regarded as laughable?

(Tangent to the tangent - this reminds me a little of Jon Stewart hiding behind "But I'm only a comedian" every time someone wants to talk about the politics in his satire. I happen to like his satire a lot and have no particular objection to his politics, but this is just disingenuous.)