FB post is solely about "literal" vs "non-literal" code copying. These are words that the lawyers chose to use to communicate a complex (for non-programmers) idea to a bunch of non-programmers.

I think of "non-literal" code copying as R&D. I think the Zenimax lawyers were claiming that the R&D that Carmack did for the Occulus, while still an employee of Zenimax, was key to making Occulus valuable. And it seems like Carmack even used Zenimax IP (Doom) to develop a demo that was shown to investors, without Zenimax permission. Essentially Zenimax was used as an R&D arm of Occulus.

Pretty messy case and pretty different from Google vs Oracle IMO.