All very true, but..
It's a first go, and it's a proof of concept.
You could easily design most of the parts for a 3D printer, and use a metal pipe for the barrel.
In the future, the materials used by a 3D printer will be developed, and there are plastics and composites that would be able to be used for a short lived firearm.
Nonetheless though, everything you say is bang on - Harlan Ellison style zip guns and numerous other improvised firearms already exist, and are better than this, but nothing, particularly not the truth, will stop the hysteria that can be drummed up by the media for this sort of thing.
Best to just chuckle gently, and wait for the reports of folks losing bits of their anatomy