Completely arbitrary is probably an exaggeration. I wrote a paper on this case for a Digital Cultural Policy class over a year ago so I'm a bit fuzzy on the details, but the previous commissioner almost settled the case and thought he had reached an agreement with Google that would pass in the Commission, but it failed to even reach a vote it was so poorly received.
If European businesses catch the ear of the Commission, it's usually to the tune of, "we're being cut off and consumers are thereby being cheated of the best deal." Sure, I omitted that from the previous comment, but the companies complaining know how to make their case, so it's never entirely protectionism in favor of European companies. I don't know if it would be possible to dispel the notion that it is always somewhat protectionism, so I won't go there.
The logic of the case made sense to me, and it follows a protocol that spans several commissioners. There are differences of approach depending on who's sitting in the chair, of course, but that's true of any government.
To return to your "Replace 'comparison shopping' with..." That's not a fair substitution. I see why you make it, I mean, they're tabs in the Google interface so the seem easily interchangeable. But underneath, there isn't a composite result returned on those searches with results from different vertical search engines like there is in shopping results (save "video" where YouTube and others show up), and there isn't the same opportunity for monetization from the search types you mentioned, so it's a monopoly powered search advantage that damages no one as presented on Google's results.
The US authorities are a bad standard in my view. They seem to be defanged puppies of the corporate overlords that bribe them into submission in many cases.
"The west!" How did I almost miss this gem?!? You make it sound as though the Iron Curtain didn't fall under Reagan's might but instead engulfed The Continent! Reminds me of Brick Tamland referring to Flyover Country as the Middle East :)