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: Joseph Henshaw was bishop of Peterborough in the East of England from 1663 until his death. Henshaw was educated at London Charterhouse and Magdalen Hall of Hertford College, Oxford, receiving a B.A. in 1624 and a D.D. in 1639.