The whole reason you can google "____ Torrent" and get results is because there are torrent trackers out there that, well, track which IP addresses have which files. The same thing that allows those to exist allows someone to watch and record who is downloading which torrents. Which is what movie studios and the like are doing as well when they send out copyright warnings based on torrenting.
The purpose of it is exactly to help you find other peers with the same content. It's a bunch of peer finding protocols on top of each other. Trackers, DHT, peer xchange, etc, etc
I mean, the data itself is all hashes, but very public hashes. Unless you hashed it yourself and shared only the hash ever, the reverse hash is a websearch away.