By that yardstick, most textbooks and eyeglasses are not free. I can't improve a textbook and put it online. I can't put my improved sunglasses on the market (even if it was non-profit).
So why are people revolted by a copywrited and patented (hence unfree) OS, but have no qualms using other non-free products?
Personally, I think free and proprietary products can co-exist. Both models produce innovations which ultimately benefit society.