Political correctness isn't really about 'preventing offense', and simplistic arguments like this make it clear you're not aware of the issues it's trying to deal with. Political correctness is mostly about not using language which diminishes people due to factors outside their control, such as race or gender. Any single such reference is not so much a problem, but when it becomes the way people speak, it very much becomes so.

PC is, on the whole, a good thing. It's just ridiculous when taken to extremes, which is the bit everyone is focused on.