Since when did it mean that because a person is social engineered to install a Trojan everyone needs antivirus? Those people who said, ‘hey this is a scam’ and not get infected don’t need one. One malware does not mean that there will be others and since on the Mac you have to actually give the malware admin rights for it to even work, much like if you are not running *nix as root, these things don’t work; antivirus is redundant on those platforms.
People just need to be educated on what not to do and they will be fine. Because on Windows where antivirus and other scanners are on every machine they still get Trojans as well. Why because people do stupid things and have to learn not to do them. This flurry of Mac users need to get antivirus is fud aimed at getting people to pay for things they don’t need which are too bloated, cpu hogging and expensive.
Your best bet is to educate your users, use diversified systems and platforms and never let users run as root on anything, especially Windows and on Windows systems have a less intrusive protection software on the system but periodically run one of the web based scanners as well. (I use Microsoft’s av and scan once in a while with Trend Micro‘s house call and other on-line tools.)
For those people that must use run as root, such as developers (and really who else needs to run as root) only run as root for the times you must and develop your software so that the user can run as a user and not root.
Anyway Apple is putting out a patch for fixing the problem and removing any infected systems of this malware.