I hope this question is on-topic for this site since it might be a bit too technical and may be too gaming related as well.
The PS3 controller can be used on Windows via programs like MotionInJoy and the open-source SCP server. However, in all programs, in order to use the controller wirelessly with bluetooth, you need to overload the OS's bluetooth stack in such a manner that the bluetooth dongle can only be dedicated for use with the PS3 controller.
I'm just wondering about the technical reasons why this is the case. Aren't bluetooth devices supposed to be interoperable via the use of profiles?