[dendory]

But isn't the point here that Microsoft doesn't want to have to build the app? Google builds YouTube apps for all major platforms but shafts Windows Phone because of their war with Microsoft. So Microsoft is forced to build their own, so they decided they will build it to be best for users, not Google, hence no ads, able to download videos, etc.

[Spearchucker]

Finding a motive from Google is difficult. Windows Phone only has 2-point-something-per-cent global market share [1], so I doubt Google sees Windows Phone as a threat to Android. That leaves "war with Microsoft", as you put it.

They must've known that this will get press attention, and companies like this weigh the impact of such attention very carefully before making a move. I'd love to understand the real motive behind this.

[1] I'm unsure of the numbers!