I generally don't find creationism offensive. While I don't believe it, I'm not offended by it. And I think that's true for most people. It's certainly not the type of thing that ever comes up in free speech arguments. I can't think of any atheist I know (although I'm sure some exist) who want creationism banned in speech or writing.
Agreed. I'm a fairly strong minded atheist and I find creationism offensive. At the same time I would defend to the death the right for creationists to have free speech.
I could understand why one might find the teaching of creationism offensive, but what is offensive about other people holding wrong opinions? I'm sure we each think the other holds several; I'm not offended by the error I perceive you might be making.