Ft Hood: How many guns is enough?

After each massacre, NRA fanatics say the shootings can be stopped if EVERYONE is armed. Here is a base which has one of the heaviest concentrations of arms in the world, including individual soldiers carrying pistols and assault rifles. But that didn't stop this shooting. So much for another specious NRA argument.
Hasan, a Palestinian & Muslim, was openly dreading being sent to the Middle East and had posted curiously positive statements about suicide bombers on his blog. What's more, the FBI was aware of this. Why didn't investigators target this guy as a potential danger? They sure seem to have a lot of blindspots, big and small. Remember when the John Ashcroft-led FBI ignored field agents' (in Minneapolis & Phoenix) warnings about suspicious terrorists' activities prior to 9/11? Sounds like the FBI is WAY overdue for an overhaul.
The Pentagon has been hyperstressing a small pool of troops, sending them into combat cycles 4, 5, and even 6 times. Hasan, a shrink, was soaking up their stress, hearing their PTSD horror stories, all day, every day.....for years. It's no accident he went on a rampage in the very building where troops are processed in from, and out to, the horror. Of course, with this huge base on lockdown, the Army, the gov't, and a compliant media will do what they can to feed the public their version of the massacre, a version which will ignore and launder the root sources of the stress and the failure to be cognizant of that stress in individuals such as Hasan and his patients.