I feel for Google a bit here. They clearly did not acquire Youtube for the purpose of inserting themselves into the DCMA discussion, which is why they default towards a "get a complaint, ban the video" approach. That way, they cannot be sued by the party claiming infraction for non-compliance with copyright laws, and they have an arbitration process in place for appeal. It's certainly not perfect, at all, but they're not in a great position to be fighting this fight given that they specifically don't police content themselves beyond actual pornography or obscenity.