To be fair, that's not an enormously crazy thing to say. If I read George R.R. Martin's work and then write the exact same story, going through sentence by sentence and changing each material word just enough to say it wasn't "copied" (e.g., "Tyrion shot the arrow through his father's heart" becomes "Tyrone fired the bolt, piercing his patriarch's breast"), I'm surely guilty of copyright infringement.

I don't think SSO should qualify for this sort of protection, for a number of reasons (it has significant functional constraints on how its expressed, it's a tiny fraction of an overall creative work of software, etc.). But it's not obviously nuts to claim it should either.