Unix was a specific piece of software from a specific era. The experience of using it was very much unlike macOS for most users. Making it a "specification" was a later ret-con.
If someday Microsoft goes out of business and whoever acquires the trademarks makes a "Windows Specification", that you can meet and be legally considered Windows despite sharing zero code with the original, I would also think that was silly.
At most it makes sense to say that macOS has a sufficient set of features to emulate Unix, not that it is actually Unix.
Unix was a specific piece of software from a specific era. The experience of using it was very much unlike macOS for most users. Making it a "specification" was a later ret-con.
If someday Microsoft goes out of business and whoever acquires the trademarks makes a "Windows Specification", that you can meet and be legally considered Windows despite sharing zero code with the original, I would also think that was silly.
At most it makes sense to say that macOS has a sufficient set of features to emulate Unix, not that it is actually Unix.