I don't care how much it offends Steve Jobs' aesthetic sensibilities, I'll keep my crap wherever I find it convenient. It's my computer and my desktop, thank you very much.
I find this incredibly difficult to believe. In fact, I'm inclined to call shenanigans: This is the worst advice you could give anyone about computer security.

You're right that security is easy on a Mac. But the worst thing you can do is become overconfident. Mac OS X won't protect you if you don't use good passwords, let other people use your admin account, leave services on when you don't need them, or don't think about what you open.

The reason I we hear about Mac threats months in advance is because there's some poor fool out there following your advice. Someone has to be the warning to others, and you're setting people up for that task.