Apple is running UNIX. Gee, like that’s ever been hacked?
Yep. UNIX has undergone a lifetime of testing by hackers... and patching by the open source community. Most of the vulnerabilities have been found and fixed long ago. There are still things that Apple has added that have vulnerabilities, but since they run on top of UNIX, they are protected from doing too much damage through those vulnerabilities.
A lot of Apple's OS X applications are also open source and the OS community also searches through them for potential vulnerabilities.