Well, okay. In that case the word doesn't actually mean much beyond "this is the way the law is". What makes the "gun show loophole" rhetoric dishonest is it has nothing to do with gun shows.
Sure, you can call it the "private sale loophole" if you want. Go for it. The agonizing over the semantic merits of the "gun show" part of the term is the same tactic as turning any gun argument into a debate over "clip vs. magazine" or "there's no such thing as an assault rifle" stuff - intentional missing of the point to derail a necessary conversation. Might even call that "dishonest rhetoric".