The article is about the impending 3D printing revolution and being able to print your own guns, not gun control in itself. I don't see how mental health relates to printing 3D guns at home.
Two things were necessary for the latest school tragedy to occur: The shooter had to be mentally ill, and he had to have access to the gun(s) he used.
Let's suppose a significant fraction of gun-related crimes contain these two elements, and it would be worthwhile to make a political push for the prevention of this specific subset. (Not to imply that any other subset of gun-related crimes is unworthy of attention.)
The obvious way to attack this class of crimes would be to remove either mental illness or access to weapons from the equation.
The article seems to be saying that denying people access to guns will become much more difficult in the next few years as new technology will make it much easier to people to manufacture them privately and inexpensively.
This implies that policy efforts in that direction will likely end up wasted, and we should instead focus on removing mental illness from the equation (presumably by increasing research to create new treatments, improving access to mental health services to do a better job of bringing existing treatments to people who need them, and reducing bureaucracy and waste).
But the article did not talk about the latest school tragedy. It talked about gun control in general, including using gun to commit crime like, for example, robbing a bank.
We've moved on from discussing the content of the article's content to how the article provides an essential link in a particular chain of reasoning about the best way to address a specific subset of gun violence.
This process is called "discussion." To me, comments that merely restate the article's content without any additional information or commentary are noise; if I want to know what the article said, I can read it directly, and I probably already did if I'm reading (much less writing) comments.
