This particular piece of malware is written for OS X (which is probably a more precise term to use than Mac; and note that it's Mac, not MAC), but it does not exploit a weakness in OS X -- rather, it tricks the user into installing it. That's not an operating system attack, and no OS in the world is safe if a user with admin privileges intentionally installs malware, even if that user isn't aware that it is malware.
The same technique would work on Windows, Linux, Solaris, OS/2, NeXT, or any other platform you can name. The security level of the OS is irrelevant if the user allows the malware to bypass the OS security.
Like I said...enjoy the ride...no operating system is without security holes....only fools and Mac (better?) owners would believe otherwise.