The whole goal of Markdown is to be a simple, easy and stable piece of syntax that lots of websites can converge on. The last thing you need is to have multiple versions of it and users having to think about which markup rules a given site is using.
I did not know that. However the article you pointed to says that they made it to convey a very serious point through humor. Since I have never seen that point made more effectively, kudos to them and I'll continue to recommend the video when the underlying point is appropriate.
The idea is obviously to communicate to the people who are part of a broken marketing process exactly how their well-intentioned efforts to improve Microsoft's marketing are failing to work.
With the hope, obviously, of reforming the process.
The flip side of this is when overenthusiastic minimalism makes something useless, like in The Onion's ad for the revolutionary (hah!) Apple laptop with no keyboard, the "MacBook Wheel" (http://www.theonion.com/content/video/apple_introduces_revol...).
The whole point in my mind is that Apple goes just so far to make minimalism useful, but not so far that it is irritating. That is what I like about Apple products, that they are usefully minimalist.
The "MacBook wheel" is not a product Apple would make because it is unbalanced to far in the opposite direction.
The whole goal of Markdown is to be a simple, easy and stable piece of syntax that lots of websites can converge on. The last thing you need is to have multiple versions of it and users having to think about which markup rules a given site is using.