Google's attempt at a defence implied that they should have checked the pages. There is plenty of internet related law to protect internet companies from responsibility for user submitted content. You can make tons of applications for tons of businesses without breaking the law, and that includes building a search engine.
In this case, Google was notified about the slanderous content on their platform. From that moment they knew, or reasonably could've known if a human actually dealt with their legal notices, that the content was breaking the law. They did not remove the material and the case was brought to court, where Google stated that they were a mere subordinate distributor left in the dark.
If they can't operate their product without dealing with legal complaints, then yes, they should hire more people or reduce the ways their search engine can break the law.
