1. The Pirate Bay's support of piracy is quite "volitional", to use the ruling's terminology. The Pirate Bay goes to great lengths to maintain its ability to enable piracy. Google will gladly exclude your entire site if you ask them to.
2. The purpose and character of Google's summaries and cached pages is quite different from The Pirate Bay's links. (In particular, Google has no intention of totally replacing the original site with an unauthorized copy, and its content is not generally useful as such.)
3. The Pirate Bay is not covered by the DMCA's safe harbor provisions (as, again, it isn't open to the idea of taking down content at the request of copyright holders).
