What? You didn't see this coming?
Every technology has an equal opportunity to be used for bad as it does for good.
This reminds me of the early '90s when people were talking of opening up the Internet to the world; the proponents could easily see all the wonderful things it could accomplish, and yet were completely blind to the possible negative uses that quickly became a reality; spam, international crime, hacking, malware, espionage, child pornography, trafficing & exploitation, etc.
And I'm sure there are things even far more dangerous that guns that 3D printing will be capable of.
When any technology becomes available to the world, you have to expect that it will be used as people see fit, good and bad. The problem isn't the technology. It's people.
