So you're saying we shouldnt teach our soldiers to shoot firearms?
Um. No. I'm not sure explaining it to you would do any good, since you still wouldn't understand.. But let's try.
The argument of the Gun Nut right is that the only thing that stops a "bad guy" with a gun is a good guy with a gun. But the very fact that they enlisted these two mooks, trained them and kept them on base, shows that before the shooting incident, these would have been considered the "Good guys with guns!"
Of course, there were issues. Nidal was showing a lot of signs of mental instability before his rampage that his superiors ignored. Lopez had issues as well. But up until their shooting rampage, they would have qualified as "Good guys with guns".
Until they weren't..