They changed their Terms of Service with no warning or grace period.
>Our new Terms and Conditions, which come into effect immediately, can be viewed at.... ....
>BitTorrent services or BitTorrent-related services. This includes, but is not limited to: "Torrent clients," "Torrent trackers," and hosting, storing or transferring "Torrent files."
BitTorrent is just a program that can have legitimate uses. Even considering illegal file sharing, you can just as easily host infringing material as normal web content. Most providers take the more reasonable stance of saying 'no illegal content'.
While I accept that Bhost has the right to change their TOS, giving no warning is unprofessional.