The only reason Apple gets little increase in security is because they're running on top of a Unix-based operating system and they can take advantage of some of the things that have been done for them.
Am I misreading this, or is he saying these advantages Apple has don't count because they're playing on easy mode with their OS design?
No, he's saying Apple got a basic level of security for free but if they don't fix their broken security auditing the issue will creep up on them (and their users) as they gain market share.
I use Unix as well, on the server and on the desktop. But that doesn't automatically make all my code secure. What made Unix more secure than the original Windows was a particular attitude. An attitude that Apple doesn't have (or maybe didn't have until very recently).
Am I misreading this, or is he saying these advantages Apple has don't count because they're playing on easy mode with their OS design?