This I can believe... OR he's using seriously outdated method information. If you're getting solid brews (which I highly suspect you are) then I would tell him that. Or maybe bring in two bottles of what you've brewed, tell him you did one with a secondary and the other long primary and see if he can tell the difference. Of course, I wouldn't bother to rack to secondary for either batch just to prove he's full of it...
BTW, I've stopped dry hopping at room temp. I add the whole hops (in a nylon bag) right before the keg goes into the brew fridge to carbonate and then serve. They get ~2 weeks to infuse their wonder into the brew before going on tap. Then they stay in the keg for the duration. Best dry hop flavor/character I've had is from that mode... :rockin: