This is specific to New York, which has banned making your own firearms. In the state I live in, there would be absolutely nothing illegal about buying 80% parts and building my own firearms. Or, if I really hated myself, buying a benchtop CNC mill, and trying to make a functioning 2011.

Tracking the sale of certain classes of items and having reams of data is obviously a huge problem; the only way to correct it would be to enact privacy laws that forbade companies from selling or sharing data with any gov’t agency without a warrant, and then limiting the warrant to a single person’s transactions.