You are violating the Terms of Service as outlined here. They make it pretty clear that pirating software is not allowed and may have figured out a way to simply stop it.
Edit: You can make the argument that you're not using it to pirate software, which I'm not here to judge, but 99.999% of uTorrent use is for pirating software so it's easiest for them to block all torrent traffic. If that's really the case.