Can someome please clarify the exact details of this WP YouTube spat?

There's been a flurry of debate over the Windows Phone YouTube saga. Some see it as evidence of Google's deliberate discrimination against Windows Phone, some see it as their just not choosing to support a small-(if growing) market share OS.

Those arguments will continue even though the saga is (essentially) over with what looks like a win for MS, in the form of a full-function official WP YouTube app. But there seems to be a factual misunderstanding underlying the debate - one I haven't seen clarified by any of Tom's reporting, which seems weird. Though we may never all agree on the rights and wrongs of Google's behaviour, Microsoft's behaviour, we can at least get the facts straight, right?

The issue is this: did Google deny to Microsoft any API or access which it has, in recent years, offered to others?

We know that Google declined to make a YouTube app for Windows Phone. That seems like their right to me. If I understand correctly, the public API that everyone can access for YouTube doesn't allow developers to make a fully-TOS-compliant YouTube app. That's why MS had to produce first a wrapper for m.youtube.com, and second an app which apparently violated the TOS in various ways, notably not including ads.

Now, not enabling proper third-party apps through the public API may or may not be fair enough in your view, but it isn't directly discriminatory against MS, right?

So far, so good. But as people have pointed out, there are YouTube apps for Wii, Samsung Smart TVs and various other services. In the famous case of iPhone, we know Google gave Apple special access to make a YouTube app - the pair were close partners back then. More recently Google's made its own iOS YT app.

But what about the more recent examples - Wii U, Samsung, etc? Presumably there is a specific kind of information/access which Google gives to Nintendo and Samsung, and has declined to give to Microsoft, that makes these apps possible? If so, what is it, and how big a task is it for Google to provide it?

To me this is quite a key detail, because if it's a huge task for Google to provide it, they can argue it 'wasn't worth their while' supporting WP or whatever. But if all they had to do was flick a switch and they refused, then it does seem like MS has been discriminated against. (Again, you may think that's fine! But let's at least get the facts clear, yes?)

I apologise if this is a long way of asking a simple question, and if everyone else knows the answer already, but I get the impression there's a lot of confusion out there.

Thanks!

tl;dr: the bit in bold.