What is Google's civil responsibility?

Here's an interesting article about a two-pronged lawsuit that's being brought against Google:
http://news.cnet.com/8301-17939_109-10278274-2.html?part=rss&subj=news&tag=2547-1_3-0-5

The first claim that Ascentive makes (though they are not the first to do this type of thing) is that Google wrongfully allows other companies to purchase ads using Ascentive's trademarks. More on this in a bit.

The second claim (this is where they are trailblazers) is that Google unfairly removes their websites from search hits. The article goes on to explain why Google had dropped their sites (due to a malware warning), but to me this is immaterial. As the legal expert quoted in the article says, there's no way this claim gets anywhere in the lawsuit. I don't see how Ascentive can allege to have any say in how Google provides search results. Despite the ubiquity of Google search in society today, we must remember that this is a service provided by a private company - the pages of google.com are not owned by the public. As a side note, not many people realize the possible implications of having so much of their data on the servers of such private companies. And those that do don't seem to care (e.g., yours truly). But that's probably a separate blog post...

Back to the first claim. At first glance, it might seem wrong for Google to allow advertising with registered trademarks. But who's really doing wrong? I submit that the fault lies solely with the company that advertises using a trademark that they do not own. Google simply provides a service - it is the other company that misuses the service. It shouldn't be incumbent on Google to check that every ad they sell does not violate a trademark.

If I were the judge on this case, it would get tossed out faster than Matt Levine at a country line dancing bar (inside joke).