"Real-life experiences" do not in fact cover everything that potentially could happen. As an analogy, did you know that a commercial passenger jet has never attempted a water landing under full control? But because we frame critical issues in "hypothetical" terms, we still make them carry life rafts, floating seat cushions, etc. Would you want those devices taken off your next intercontinental flight just because they deal with "hypotheticals"?
Security means planning not only for those contingencies that have occurred, but also those that haven't. With regards to a Mac, that means that security requires being prepared for a security failure in a single piece of software (in this case, OSX) even though such a failure may never have occurred before, and even though the software may be designed to avoid a failure. Unless you want to claim OSX is perfect, making it unique in millions of years of human endeavors, it's irresponsible to ignore any such risk.
It is insecure because Windows is a piece of crap, built to become obselete the day you purchase it, and built to satisfy the non-thinking consumer and the corporate executive who only thinks about short-term costs, not long-term consequences of purchases.
On a side note, you really don't do yourself any favors by insulting people with whom you're having a discussion. If such is more your speed, I guess I could just save my time discussing security and just call Mac users a bunch of "gay commies".
I work in risk management. RM does not try to cover everything that could potentially happen. That would be foolish and impossible and time-consuming. Assessing risk takes some wisdom and a clear knowledge of what is going on the world, not what you are afraid "might" happen.
The anti-malware out there can only protect you against LAST WEEK'S Malware.
As it stands right now, our Macs are just as secure against a Zero Day virus as your loaded to the gills with anti-ware PC... because you can be invaded by a virus that has not yet been cataloged in the anti-virus definition file. The Macs are just as secure WITHOUT all your CPU cycle robbing anti-malware baggage and until the day we see ANY viable malware in the wild, it will remain so.
When, and if, a viable Mac OS X malware appears in the wild, THEN, and only then, will it become necessary to consider buying and installing malware protection.
However, when that does finally happen, if ever, our Macs will still be just as vulnerable as your PC against all Zero Day, unreported malware. Buying protection against non-existent threats is foolish. When there are finally preventablethreats, not buying protection would be foolish. Until then, I'll save the money.