You don't have any idea what you are talking about. Deep Packet Inspection has been on providers' plates for years and they implemented to snoop into your data stream to determine what you may be sending and or receiving that might be considered illegal.
He's right though. The ISP's are not actively looking at packets (for this), they are waiting for reports from content owners. They are getting that data simply from torrents and recording the IP's that are shown in peerlists and sending them to the owners of the IP's.
Now, if they own one of the content owners..that's another story (didn't someone say Comcast owned one of them?). There was throttling involved with P2P traffic in the past (maybe still is), but it was for different reasons.