Was going to say the exact same thing, but I'll go further. Because we know an inanimate object is not evil in and of itself, but the person wielding it, that person could have passed a BGC to acquire their firearm 5, 10, 20 years ago. But today, they may have committed violent crimes in that span, maybe even been convicted of those crimes and squirreled away their firearms to a family member or friend, and now want to purchase or trade for a firearm. While my libertarian desires easily conclude that this is the price we pay for freedom, my more logical side says that having a BGC (while inconvenient and costly) makes sense.If you are just looking for a reason, and you aren't, its because a lot of the people who have guns aren't allowed to own guns. Ive seen that as a dealer.
The truly unfortunate reality in all this is that because the ATF only refers less than 1/10% of 4473 violations to a US Attorney for prosecution, it falls on the firearms dealers to weed out those who shouldn't have firearms. And those stories never make it on the news.