Yeah but what about CNC milling machines? Way more guns are made on those every day than 3d printers. There is even one you can buy that is specifically for making "ghost guns"
A CNC mill that's worth the cast iron it's made from weighs at least 2000 lbs, not to mention it takes a lot of skill to use (workholding, toolholding, setting up feeds and speeds, coolant, etc). It's very easy and very expensive to crash if you don't know what you're doing. A g-code program has to be modified to fit your machine, where the origin is, the dimensions of your rough stock, what tools it expects to have, how much material your machine can hog off.
In contrast, a pretty good 3d printer costs $500, can sit on a table, and the inevitable mistakes you will make while learning how to use it are comparatively cheap.
I'm way more worried about drones, self-driving cars, and humanoid robots than "ghost guns".
Once these things can move around us, far away from their owner, there is enormous potential for societal harm.
Someone could buy a $10k Figure robot, strap a bomb or nerve agent to it, then have it walk into a public place.
If we just accept these robots as normal everyday things (it seems like we will), we wouldn't even blink or think twice that a robot was walking up to us.
I hate monitoring and tracking and surveillance. I'm a freedom and personal liberty absolutist for most things without negative externalities. But as I put this new AI tech through thought experiments, I don't know how we'll survive in a normal world anymore when agency is cheap and not tied to mortality.
Society, even one with guns, relied on the fact that people are afraid of the consequences of their actions. If there's no ability to trace a drone or robot, god only knows what could happen.
Kidnappings, murders, terrorism. It seems like this might become "easy".
How hard is it going to be to kill off political opponents in the future? Putin, for instance, enjoys relative freedom of movement because it's hard to get close to him.
Once you can throw a drone into a field or rooftop and have it "sleep" for months until some "awake" command, then it operates entirely autonomously - that's cheap, easy to plan, and potentially impossible to track.
Some disgruntled guy buys some fertilizer, a used van, and comma.ai?
We potentially have a very, very different world coming soon.
Mentioned in TFA