In a brief, but much needed forum post, Bungie's Nathan Bitner offers a few words of wisdom:

Look, we don't even know here who would have said that. So take anonymous sources with a grain of salt. Lord knows, you guys should have learned that by now. ;)

And by the way, for what it's worth, it's infinitely easier to port TO the Mac than FROM the Mac; perhaps that's the answer to many of your questions.

Sound advice. Believe nothing that you hear, and only half of what you see...