I don't have a problem with background checks, as long as they do not retain the information. But, you can never trust the government not to lie. The background check is, in effect, a de facto registration with the federal gov't.
If, and a major if too, they do not retain the data on your purchase, they just might retain the data that you made a purchase - same thing.
And remember, under the commiecrats now in power you can expect more requirements being crammed down your throats. JMTCW.