Scenario: Google runs Microsoft software, is attacked by hackers. Google has to wait on Microsoft for knowledge/patches to security holes, even though Windows h

Scenario: Google runs Microsoft software, is attacked by hackers. Google has to wait on Microsoft for knowledge/patches to security holes, even though Windows has great security. Logical reaction: move away from Microsoft products due to nature of platform. That I get. Google runs Linux, is able to patch things up whenever holes occur due to the open source nature of the OS. A move to Linux makes sense to me. What I don't get, however, is the bit where OSX is allowed. My theory is that Google made the switch not because OSX and Linux have better security per se (that is, as compared to Windows - because tctacek is right, Windows is rather good with security) but because having a userbase of so many different flavours of Linux and a spattering of OSX is going to be hell for future hackers. Does this make sense?