I couldn't figure out why Google wasn't getting pissy AT ALL over Cyanogen forking and talking smack about them..
Much more basic: Ask your self, *WHAT* is google's business, what are they earning money from ?
They are not earning lots of money buy selling copies of Android.
Instead they earn money with their service: they probably earn a percentage of sales of apps on their store, and they earn tons of money through their data-mining/advertising.
So yet another fork of android doesn't mean less revenue for Google. It means yet another portable platform that will eventually log into maps.google.com, and ask about pizza, and earn them tons of money.
It's the same reason why google can at the same time support Firefox development (they pay them a good budget) and at the same develop their own browser.
That might sound weird. But it makes sens. Google isn't in the business of *selling* browsers. More browsers mean more people online eventually using their service, and thus means more indirect profits, no matter exactly were the browser came from, as long as it conforms sufficiently to standards (HTML5, etc.) and can use their service, and isn't completely married to a competitor service.
The only thing regarding to Android that would drive them mad a little bit, is if Microsoft decided to fork Android, and design a special fork that only exclusively works on Microsoft's services (Bing, Office 365, etc.).
Lukily for them, Microsoft did instead attempt to make such a microsoft-exclusive platform using their windows OS and we all know what kind of success they had with this.