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: Thubten Yeshe was a Tibetan lama who, while exiled in Nepal, co-founded Kopan Monastery and the Foundation for the Preservation of the Mahayana Tradition. He followed the Gelug tradition, and was considered unconventional in his teaching style.