Google promotes Goole?
MS says that F/OSS systems cost more than MS ones?
Yahoo ranks Yahoo higher?
Business analyst discovers water is wet?
Is it really any surprise that Google promote their own wares? I mean, is it? All companies do this, it should come as no surprise to anyone. Maybe Google will claim that their sites are in some way "better" and so deserve higher ranks. "Better" meaning "easing for our algorithms to deal with".
That shouldn't be a stunner either. Their engineers know the algorithms, so it's a simple matter of massaging the site to match the algorithm. It amounts to the same thing, but does allow Google to state that their algorithms (not sites) are not biased.
Now if you will excuse me, I must investigate ursine religious demographics and arboreal papal defecation.