I hate to be dystopic, but what happens when a futuristic Unabomber gets a hold of 3D-printing, self-replicating robots and programs them to kill? Will we all

I hate to be dystopic, but what happens when a futuristic Unabomber gets a hold of 3D-printing, self-replicating robots and programs them to kill? Will we all be walking around with our own 3D-printed bodyguard robots, programmed to watch and destroy any other robots that look hostile? Or will the first bad actor's robots destroy everyone else's (or everyone else)? > Then everything will cost only as much as raw materials. Seems like one would want to own the raw materials, then. But if the evil Dr. Robotico's robots can kill the owners and take their quarries, then what? Does he rule the whole world? Are we in a race to robot armageddon? Man, that Paperclips game is starting to seem more and more prescient.