Guns are not the problem; mental illness is, says the National Rifle Association after each massacre. Its not clear what they mean, but lets assume it is that the pendulum has swung too far and it is too difficult to confine mentally ill people to institutions involuntarily. That may or may not be true, but it diverts attention from the real issue whether unstable individuals should have access to guns. The answer is obvious, but the standard for involuntary confinement can never be adequate to the task.
Other than the right to live, no right is more fundamental than liberty. The right to keep and bear arms recognized by the Second Amendment, which includes the phrase well-regulated, is not on the same level. Recent Supreme Court opinions held that the Second Amendment contemplates an individual right to guns; they also made it clear that this right is not absolute, but subject to reasonable regulation.
In terms of both the Constitution, simple fairness and common sense, it should be more difficult to lock a person away than to deprive him of access to guns. Conflating the two rights, and the two standards, is utterly wrong and, to put it mildly, unhelpful.