That isn't completely true. I can transfer a domain name to you without any information at all other than your registrar account name...
A domain isn't a physical good. I expect that hilarious is referring more to places like the 'Collectibles' subforum, where actual physical items are bought and sold.
Based on checking his feedback, he hasn't sold any email forwarding since he was removed from DT2. That confirms your theory as of why people bought it.
It's likely a similar story to what happened with bigtimespaghetti and his coin making guide.