This is very slippery reasoning. If this person were speaking to you in person would you look at it the same way?
Of course. To be offended by an arbitrary sequence of sounds is completely irrational. It is the meaning of those sounds that can be offensive, and the meaning of them is whatever the speaker intends them to mean. If they are not intended to mean something offensive, then they are not offensive (the speaker doesn't have to agree that the intended meaning is offensive, but you can't argue with the speaker about what those intentions are [unless you suspect the speaker of lying about his intentions, I suppose...]).