No one, in a democracy, has the right to not be offended. If so our society would implode. Doing one thing offends someone, but not doing it offends someone else. We aren't a collection of unstoppable forces and the immovable objects, we are people, with feelings, and the ability to get over ourselves.
There are limitations on what one can say, without the expectation of legal repercussions. One cannot lie about someone, in spoken word or written, without potential repercussions. Nor can one spout hate speech (communication that carries no meaning other than the expression of hatred for some group especially in circumstances in which the communication is likely to provoke violence) at one's whim.
But, barring slander and hate speech, we are lucky enough to have the right, the freedom, to say whatever we like to whomever we like, regardless of whether it might offend that person. It's one of the things that makes living in America great. I don't have to worry whether my offhanded sarcastic comment will get me thrown in jail. Now, such comments might prevent my promotion, make my coworkers less inclined to go out of their way to help me, or otherwise make my life more difficult, but that's another can of worms.