No, comedy can still be offensive. Anyone suggesting comedians can't be offensive is lying. Comedians routinely punch down, and routinely sell out shows. The believe that comedian's can't be offensive is a shtick they are using to market their shows to an audience. It's all advertising and marketing, and the gullible eat it up because it feeds into their bias.
Conceptually, it's clearer to think of offense as a relation, not a property. This is because offense requires a specific audience and a specific context. Content alone is not offensive.
