I understand the intent, but feel that there are so many other loopholes that put much worse weapons on the street than a printer. Besides, my prints can barely sustain normal use, much less a bullet being fired from them. I would think that this is more of a risk to the person holding the gun than who it’s pointing at.
In the US you don’t need a license to purchase a CNC. Even items with export restrictions like night vision goggles (Under ITAR) can be bought by anyone and shipped to your door. The export controls would only come into effect upon you exporting them.