...seriously? Are you that thick?
Because their UI is their proprietary skin. They developed it themselves, and have decided not to share it with the LinuxMCE community, that's their choice.
Dianemo is on a very different track from us, and while Uplink does push code changes to us from time to time, their own pieces which are NOT released as GPL or PPL, do not have to be pushed back to us.
-Thom