Considering for some years now, Penn & Teller's whole act is basically exactly what this guy did, I'd chalk his shunning down to him trying to protect his identity (yes, in the last episode, he dud reveal himself, I know... but I suspect that was not entirely voluntary.)
I've seen P&T's show in Vegas a few times, and I've seen many of their TV appearances. They do explain how illusions work, but they don't spoil other magicians tricks. They will do an old classic, show it from the "other side", and then while you aren't paying attention they pull off something new, giving no explanation for that one.
Given their popularity, I'm sure they've been allowed back in. :-)