There is a philosophy that underpins a lot of the technical world - not just Google - that the human race is entering a new age where intellectual property rights just will vanish into "the cloud". If you ever casually reused an image without being certain you had the right, or if you ever took a copyrighted song or movie from P2P or the torrents, you may be sharing in this same mindset.
Given the technical tools that people already have, a major change in the legal concept of IP rights is probably inevitable - if not its complete disappearance. Maybe we can blame the Grateful Dead ;) and the way they encouraged bootlegs.
Sometimes Google does things that are aligned to this emerging hive-mind-cloud of "no individuals" - and the way scrapers and mash-ups get ranked is a sign of it. And sometimes (Youtube and the recording industry, DMCA compliance, Google Books) they can be pushed into honoring the way things are today, rather than some futurist philosophy. But it does seem to take an outside push to make it happen - honoring IP rights is not a core purpose.