Activision Blocking Linux Gabriel Knight Re-release

The Pinkerton Road forums reveal that the upcoming Gabriel Knight: Sins of the Fathers 20th Anniversary Edition will not be released for Linux as originally planned (thanks Xil via [Phoronix]. This is the doing of rights-holder Activision, but even the developers at Phoenix Online Studios are at a loss as to why:
Figured this deserved its own thread. I hate to be the bearer of bad news here, but my previous statement that GK would be available on Linux turns out to be incorrect. I can't even begin to imagine why, but Activision isn't allowing the game to be made for that platform. Just PC, Mac, Android, and iOS devices.