From my limited knowledge of the situation, this seems an appropriate fine.
Google claims that the success of Ebay and Amazon prove that they haven't been anti-competitive, right?
But I think Google just couldn't help itself.
How could you not?
You have the consensus, world dominating search engine, and you just have to slightly tweak it to every so slightly support your shopping platform.
It just seems way too easy to do.
One small adjustment means $4 billion more next year, I mean, how could you not do it?
As an anecdote, I have never trusted Google's product results in the top bar. It just all seemed to easy to fudge the results to me.