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: John Carney is the managing editor of Clusterstock and a contributing writer at The Business Insider. Carney is a practicing attorney who graduated from the University of Pennsylvania, before practicing corporate law at such firms Arps, Latham & Watkins, Meagher & Flom, Slate, and Skadden.