madvr is a third-party DirectShow plugin that MC uses. But they don't make it, madshi does, and he makes it for Windows.
The goal of the built-in Video player in MC is, I think to eventually replicate as much of madvr (or what MC uses of it, at least) as is possible for OSX and Linux. But, it is basically brand new and certainly does not match Red October's full feature set on Windows.
By the way, I can't see in that MadVR Expert Guide any notice that it's not applicable for mac version. Seems it's some defect of this guide.
The Wiki has some cross-platform applicability. Lots, in fact, but... I agree, there is no consistent "tagging" of articles that apply to Windows-only, or Mac-only, or cross platform. I've had it on my list to make a template to do this for some time, but I haven't decided on a good style. I'd like some kind of "footer box" that can list what OS and what version an article is applicable to, but... Too much stuff, basically no time.
For now, I did make
this list, which is "stickied" to the top of the Mac board.