This is misleading. Not sure if by ignorance or malice, but it's very misleading.
This isn't happening with your browser bookmarks. This is Google Collections, which is a shareable bookmarking feature, meaning it can be made publicly available. That's why it's moderated. It's basically Google's version on something like Pinterest.
They have a duty to moderate public-facing systems. This is a link/bookmark sharing system, so obviously bookmarks that are pointing to things that are illegal are going to be dealt with.