I tried it in pretty much all broswers, Firefox, Chrome, IE, Safari...none of which showed the desktop version, until I click on "Standard Version" at the bottom...this happened on both Mac and PCs both in my office and also in my clients as well, so it is not just a fluke thing on my browser here...
This is what I see when I go to that link you posted: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:17.0) Gecko/20100101 Firefox/17.0
I have no other modules installed, I literally installed Mobile Joomla and didn't touch anything else....I thought it was having Mobile Forever enabled but I disabled that and still did not work.