PirateProxyList – Online Status of Various Pirate Proxy Services
pirateproxylist.com
pirateproxylist.com
Also for future reference, there's a difference between a tracker and an index. Trackers connect a peer to other peers with the same torrent, whereas an index just lists torrents. I'm not saying this to nitpick, but because it can get really confusing if you don't know the difference.
As for why they don't do that, I wouldn't be surprised if the answer was "legal reasons" or "lack of resources". "Never attribute to stupidity that which is adequately explained by lack of time"?