Not as easily. With torrents you don't need access to the servers (seeders/peers uploading), where-as with Usenet you will need to ask the ISP for server logs, in which case most ISPs will respond with you first need to get a warrant before they will just give out information on their users.
From my side, I am way too lazy to dig through logs, and clients give us money, so its easier to force them and ask for a warrant.