Guys, let's not get up in arms here. My take on it is this - since the USB interface is agnostic to the actual data being transferred (Just like TB for the record) it is nothing like a dedicated mDP port on a Mac. Of course those would not work with Thunderbolt, because they were not connected to any kind of data bus on the other end, just video/audio, that makes complete sense, and you guys are 100% correct, that is totally undisputed. It also is not what I am talking about at all!
Like TB, USB is an all in one, power/data/video/audio capable system bus. Apple's adapter is a "dumb" adapter. You're right that it has nothing to do with mDP. It doesn't expect to connect to TB necessarily either, it just converts the Ethernet signals to signals on specific pins in the male end, which happens to be mDP. It is the system bus' job to interpret those received signals, not the adapter's. It's not like Apple's Lightning adapters that are active, dynamic and digital, where the pins can take on different functions with software on the tiny little microchip in the adapter. We're talking about old fashioned mechanical fixed and static pin configurations.
Of course Apple's support site says you need to have a Thunderbolt enabled Mac to use the adapter, because they are making sure people don't buy it to use with their existing older mDP only Macs.
Do you guys understand what I am trying to say?