Yes, we are aware that in this day and age one needs to have Mac support 🙂 We had to pick a platform to start with and we chose Windows.
The EyeX Engine is quite a complex software component that handles everything from the eye tracker configuration with calibrations, screen setups, providing settings, saving user profiles, and then providing a high level EyeX API that is more than raw gaze data. It is not trivial to port or re-implement this for Mac.
As for future plans, there are no concrete plans on when or how to support EyeX on Mac. But there are plans to support the Tobii REX eye tracker and have a version of the Gaze SDK for Mac.