Well that's Apple! As always they try to control as much as they can. They're worse than Microsoft in the early days and we all know that ms didn't even respect laws to succeed in business. So we end up with Vulkan, DX12 and Metal, well then cheers.
Thats a harsh reaction to making an API available on more platforms then it was before... what do you suggest they do? Keep using old OpenGL? Wait for Vulcan to arrive? Implement DX12?
I think it would be pretty nice if there was just one api for everything microsoft and just one api for everything apple.
Of course, it would be even nicer with just one api, that also worked on everything else, but not that bad situation...