Wizardly books can be shared in the reading thread, wizardly movies in the movie thread, etc, even in the form download links to torrents and tracking sites. I think there's a thread in /jp/ for pirating Japanese goods. Creating a whole board for BitTorrent would just create a divide between those who do and do not use torrenting so similar discussions would be split redundantly. Additionally all IPs currently downloading any given torrent can be viewed by anyone else downloading the same one, so one could potentially farm user IPs by posting an obscure or fresh torrent and monitoring who attempts to download it. Furthermore that curious baiter could then use a public lookup to see what other torrents that IP has been downloading. Such a bad idea when you get in to the privacy risks.
Please avoid pasting hashes as that requires someone to open it and verify that's it's not a troll or spam