OS X should be agnostic about the software running on it. If you fix it for Emacs, then it should also be fixed for vi users and nano users, etc. some of which are mutually exclusive.
A company can fix a problem without sponsoring a product associated with the problem, just like a company can release a product for a competing platform.
He doesn't want the key binding to be Emacs-like he wants to go back to being the way it was before this random change, the way he had already gotten used to. That is, he wants it to be Apple-like again. (It happens that the old Apple way and the Emacs way coincide, which is probably what confused you.)
https://bugreport.apple.com/