Sure, and I'd even seen some of that before. I didn't intend to say that Apple precisely borrowed Linux code, hence the *nix I was using. However, at the broader level, I did mean that when their own core code went to pieces, they went outside indeed and it was much easier to borrow the Mach kernel than rewrite a brand new one all over again.
So my comment was about how they borrowed some open source core code and turned it into one of the most locked down platforms in history.