Oh believe me I know it has origins in ivory towers like MIT. Stallman has written all about that for instance. The context with GP was once it had trickled down into more popular culture with the ESR / Jargon File days. We honestly don't know a lot of the true origins of hacker culture, because so much of it started in corporate government enclaves with confidentiality rules. What we know are echos of practices and socialization that crystalized into usenet posts.