Brad-
The idea of hardware having back doors or even malware built into them is nothing new. Supposedly the US identified the Sony hack as North Korean because of information supplied by, gee, code we put into their internet routers. Not to mention, the STUX virus, which destroyed Iranian atomic equipment supposedly was US-sourced.
But if you read the link you posted, it says right up top
"Update: Lenovo has been in touch with the following statement:
Lenovo has no additional comment on recent reports in the Australia Financial Review. We would like to point out the public statement by the Australia Department of Defence available on their web site that says “This reporting is factually incorrect. There is no Department of Defence ban on the Lenovo Company or their products; either for classified or unclassified systems.”
IOW, there has been no official confirmed finding of any back door. This story has as much credibility as the one that Proctor & Gamble are devil worshippers, because their logo contains 13 stars. (Oh, wait, so did the first US flags...)
OTOH you will find that the CERT program, run by Carnegie-Mellon University and the US government, has repeatedly said that all UNIX OSes and their variants suffer from malware and attacks just as much as Windows versions do. And, that Apple themselves have released several major security updates which they simply refused to comment on, which served nicely to stop publicity about them. Apple's OS happens to be a version of UNIX, in case you didn't know.
So while you may hear less about Mac hacks, don't feel secure about it. Macs are being hacked every day, and as PC and Android security increases, the hackers also know that Mac users tend to have higher incomes (fatter targets) and less knowledge of security, because they deal with it so rarely. In other words, they know you're prime beef on the hoof.
It's a *different* OS, but that doesn't make it better or worse.