Oculus founder Palmer Luckey was asked during an interview when the will they be adding Mac support to the Rift. His answer was simple, when Apple releases a good computer.
Other than being the burn of the year so far, it’s also true. Luckey’s reasoning is that the current Macs simply do not have the graphical power to run something as intensive as VR on the Rift. Even the most powerful Mac Pro, with dual AMD FirePro D700 GPU, falls short of a single NVIDIA GTX 970, which is the minimum requirement to support Rift on the PC. Apple never prioritized gaming on the Mac and all the current machines are non-user upgradable now so you can’t just install a more powerful graphics card like you could with the older Mac Pros. Even if Oculus added software support for OS X none of the machines will be able to handle it.
Apple has shown an interest in VR recently but without the hardware support to match it’s pointless.