That's the point - willingly saying that they promote spam sites to milk ad revenue could land them in antitrust trouble. But all they have to so is merely not do anything that would downrank said spam sites, and the outcome is exactly the same yet they are now legally in the clear and can just blame incompetence for the (totally predictable) outcome.

I mean that is exactly what each and every Google team does. There is no decision being made without having the data "supporting" it.

But every graph can be shown nicely and things which are common sense don't need a metric to proof it.