Comment by wkat4242
They could though. They're just being overly cautious.
All it forbids is blocking users from running modified FOSS code which macOS doesn't do. You can compile what you want and run it in Xcode. Even on iOS you can do this.
What TiVo did was shipping FOSS code but not giving users any access to their device.
But Apple enforces code-signing, and that prevents them to ship those binaries under GPLv3 in the OS. The users can always compile them on their own (or via their favorite package manager) but Apple just can't ship it (without changing how they operate fundamentally.)