"Monthly? Software Removal Tool?" How old are your Windows versions, guys, and where have you been hiding? Windows Vista and Windows 7 receive updates for the built-in "Windows Defender" - as it is actually called - almost daily. And if you want some real anti-virus software on your system, you can also install the FREE(!) Microsoft Security Essentials on your system, which are as good ESET NOD32 or other pay-for anti-virus software suites.
Anyway. The only real news here is that Apple for the first time ever officially acknowledged the existence of malware for Mac OS X and that OS X can actually be infected. So much for their "Macs don't get viruses" campaigns. Even back then there was malware for Mac OS X, Apple had only comfortably ignored that fact and lied to its customers.
But since more and more of those malware-for-OS X-reports have been surfacing during the last couple of months, it's rather obvious that OS X has become attractive for malware authors and that the platform is nowhere near as secure and safe as Apple and their customers always wanted to believe. (Just let's not forget the amusing fact that OS X still comes with its Firewall DE-ACTIVATED in the default system configuration; that already tells us enough about how serious Apple takes security.)
No platform is absolutely safe and secure. It's just that nobody else runs around with a big mouth and pretends to be immune to threats, and everybody else - including Microsoft - patch and update their software quicker and more regularly than Apple.
Anyway. Welcome to the real world, Apple and Mac users.