y question is why - if it doesn't exist to begin with - are so many people opposed to closing this loophole
HUH?!?!? If it doesn't exist, how can it be closed?
It does NOT exist - period. Folks are free (in most states) to sell their private property to someone who wants to buy it. They are free to sell guns at garage sales - been there done that - through newspaper ads - again been there done that - or in the parking lot of ....(fill in the blank).
Some folks prefer to hit a target audience - those found at gun shows. no different than you taking your used car to a car show and trying to find a buyer, or your lawn equipment to a garden show, or any of a number of alternatives analogies