I can't see things like this as anything other than a step in the right direction. Greater individual access to manufacturing capability, to whatever end, can lead to many unfortunate consequences... but far more often than not it can and I believe will lead to a technological renaissance where innovation is possible for anyone who's willing to take a risk on their dreams. That applies to all technological advances which trend towards empowering the individual over the collective. To name just one benefit, the more we disperse our technological base, the less likely it is that some manner of catastrophic failure of society/civilization will cause another Dark Age. Developments like affordable small-scale manufacturing make our entire way of life much more resilient.
And just for the record, mass-produced, cheaply made firearms which do not explode when used are something I see as a major net gain for human rights. It is exactly this sort of technology which breeds equality, in a way no law ever could. It means that a poor family living hand-to-mouth can have access to a means of self-defense which as of right now might otherwise cost several paychecks' worth of groceries. I support this new development as I do the efforts to deliver cheap educational materials, computers, and internet access to those who still have to make do without the modern conveniences we use every day to exercise our right to free speech. Every basic human right is and ought to be for everybody, not just the people who can afford to jump over hurdles to reach it.
I can't say I'd bother owning one except perhaps as a novelty... I've already got better. However, I wholeheartedly hope that the knowledge spreads beyond any one person, organization, or government's ability to censor it. In the end, freedom is what it's all about, and there is no freedom, no humanistic imperative I can imagine more basic and essential than the right of every single thinking, feeling being to preserve his or her own life and the ability to secure that life from the whims of those who would wish to dictate its course.
. Besides not wanting anymore grief from big brother i have no use for that,dont have a 3d printer and wont be buying one,i get enough enjoyment out of building up parts kits.