Honestly, I’m not surprised. Not just because of their lack of privacy (them knowing your bookmarks), but also legally. Some countries are trying to crack down on piracy, and other illegal material, asking companies (like Google) to do this.
It doesn't feel legal. A bookmark is textual data you've stored on your computer for later reference, and while it is on their application, somehow this feels wrong. It's definitely wrong ethically, but is there something in the user agreement that says they have full reign of whatever the browser can touch?
Pretty much everything you do on Chrome gets sent to Google. It is one of, if not the worst browsers, for privacy. Their Privacy Policy is pretty clear on this. It’s all for a better “user experience”.
If you actually let bookmarks be local textual data like you've implied, this is actually true - Google can't interfere with them.
The 'Google is deleting your bookmarks!' thing only applies to those who log in to their Google accounts on Chrome, enabling sync, in which case you're not storing favorites in your computer. You're storing them in Google's servers and your client is just replicating a local cache of the data that is now Google's.
Actually this is only on Google Collections which is a bookmark sharing service, not just the browser bookmark sync.
Your synced bookmarks should be unaffected as Google says everything in browser sync is encrypted locally before being synced, so Google shouldn't be able to scan those (or really care about them at all)
They are doing it to protect themselves from legal liability specifically because of the public-facing nature of Google Collections bookmarks.
They don't care about your synced bookmarks or browser history because it's not public-facing and they aren't legally liable for the contents