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: Moschus, ancient Greek bucolic poet and student of the Alexandrian grammarian Aristarchus of Samothrace, was born at Syracuse and flourished about 150 BC. Aside from his poetry, he was known for his grammatical work, nothing of which survives.