The blog post explicitly says they're choosing to "defer the issue". That seems very clear to me as saying "we're not seriously proposing the Metal Shading Language, this is just a placeholder for the purposes of writing up this proposal, we'll let the standardization process decide on the actual language".
I understand what the text literally says, my point is that if a company proposes a strawman that is literally just their proprietary solution on the web any one liner disclaimer that says "but we're not actually necessarily proposing that it use our proprietary solution for this (but maybe!)" can be reasonably suspected as potentially being disingenuous.
There's a whole standardization process to this, which everybody can participate in. The whole point of the proposal is to kick off the discussions and standardization process. Literally nobody expects the proposal to be standardized as-is, so I don't think there should be any concerns whatsoever about the fact that they punted on designing a new shading language. Standardization isn't a "yes or no" vote, it's a process by which the proposals are modified again and again until they come to a solution that everybody is willing to accept. It's simply not possible for Apple to force everybody to accept their Metal Shading Language.
