I'm torn between "That's almost cute" and "This is wrist-slapping ourselves to give the appearance that we administer our guidelines in a manner which is not arbitrary and capricious."
I'm sure trying to decide which snarky remark best conveys your condescending attitude towards a company's attempt to maintain its integrity and good standing is such a terrible dilemma.
If Google's integrity and good standing depends on not manipulating search results, there isn't a relevant case study for making such a determination - Google is still manipulating search results relative to Chrome.