Well I think that is a joke with regards to ninetendo; while I expect to see it on linux and macos (dont' have a mac myself); as well as xbox and ps4 - i have no clue which platforms will obtain the actual ports and in what order. If it was strictly up to $$ I would expect xbox and ps4 before linux/macos (er not $ to cost but $ to be made). D:OS 1 runs pretty well on all these platforms but i'm unsure what has changed in the engine with regards to hardware interface - it might be that they all will work in the end without little effort (beyond qa) or it might be that the graphic improvements were not done platform independent. I suppose you would require one of their coders to comment on the engines layering and structure to have a feel for what will happen and in what order
The company line is of course the standard line because it avoids liability to claim something and then (for whatever reason) failing to deliver. I would prefer something like:
we are focus on windows but intend to support x,y,z but at this time we cannot promise that will happen as circumstances will change. Obviously the statement they are providing is more conservative but it also leaves the user base further in the dark which is less satisfying. Then again if they said something like the above an then had to back out (for whatever reason) people would be (more?) angry.