Yep that's exactly how I interpreted it ... not because people are adhering to some sacred oath given deep in cavern in a secret location ... just that someone invented something new and unique, they are rightfully earning some money from that effort, and you could potentially destroy the whole thing simply by posting too much information about it. As you said, that would certainly be a "dick move", and since a lot of people don't want be that, they don't do that. In the end it seems to be pretty effective.
I still want answers to some of the tricks that I've seen on Penn and Teller's show. Some of them do come across as impossible no matter what way I try to think about it.
Dani DaOrtiz comes immediatly to mind ... no clue how it's done but he's pretty funny. This particular routine has various elements that each seem to be impossible.
And honestly, I don't want to know how it's done. It's magic.