Trojan software exists on ALL systems. This is nothing new.
Anyone can write a program on Windows/Unix/OS X to do ANYTHING. That's really the point of personal computers. There is nothing Apple/Microsoft or anyone can do to stop this outside of using their approved app stores where they can take down a malicious app like this.
This article is just iHater bait to people who don't understand how software works. A virus or worm is a different thing. A trojan - can happen to any operating system at any time. A trojan is basically software that says it does one thing then actually does something else. That's what Apple's App Store helps avoid, apps like this. This proves, again, that the Apple closed app store protects users better.
And also in this case, the user had to connect to a "special" app store to download an OS X app. Not to mention, this malware is largely targeting the identity and SMS of the victim. This is very Big Brother type of info-hacking. I feel for the Chinese citizen.