This is the way to more piracy. No one is pirating Ubuntu, but who has actually bought a Windows license? The less freedom there is, the more piracy there is.
Sorry, Maybe I am missing the point but you are saying that by removing one mechanism to piracy you are actually forcing people to pirate and that people who search for torrents via google aren't going to use them?
Google are a corporate entity. It's up to them how they conduct business. If they so choose to exclude torrents then they can do that. If you so choose to not use them, well, there are others out there. Consumer choice.
If you want to download a legal torrent, e.g. unbuntu it doesn't take a rocket scientist to type 'unbuntu' into Google, go to the home page, download, torrent, done.
I think Google is making the right decision here. As a big company they are one of the few who can make an impact on piracy. They can also save themselves money by not having to scale up hardware to meet the demands of those who are using it just for illegal file sharing sites.
Good on Google.