BSD is usually not unix certified, so has to refer to itself as unix like.

Wait, really? Not POSIX? Huh

Also another reason I doubt current version macos is certified is:

“Because it’s an expensive and lengthy process. And every version will need to be re-certified.”

And what always gets lost in these discussions is if that old Unix stuff was so amazingly good that we should automatically assume Linux is inferior for not doing it. Even though all the old Unix vendors are basically dead now and replaced by Linux.