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 general, most people can legally build their own firearms in the US. “Ghost” guns aren’t illegal unless you’re selling them or giving them away.