Linux is not in the public domain. Linux is a cancer that attaches itself in an intellectual property sense to everything it touches. That's the way that the license works.
Bio: Hasegawa Nyozekan was the pen-name of Hasegawa Manjirō, a Japanese social critic, and journalist in the Taishō and Shōwa periods Japan. He was one of the most important and widely read supporters of liberalism and democracy in inter-war Japan.