I would think that, in most cases, jargon would cover topics that aren't easily handled by commonly understood language and would be difficult for insiders to communicate to outsiders. "I could explain what we mean by defundibulation, but you would need at least an undergraduate degree in Reverse Quantum Psychology to understand it." It then becomes easy for the outsider to conclude that the reverse quantum psychologists really don't have anything useful to say and are just using the jargon to cover that fact up.