Unless the jargon perpetuates a false dichotomy, or otherwise obscures relevant content. In politics, those who think in terms of a black-and-white distinction between liberal and conservative may have a hard time understanding positions that fall in the middle (or defy the spectrum altogether). Or, on LessWrong, people often employ social-status-based explanations. We all have the jargon for that, so it's easy to think about and communicate, but focusing on status-motivations obscures people's other motivations.

(I was going to explain this in terms of dimensionality reduction, but then I thought better of using potentially-obscure machine learning jargon. =) )