Ft. Hood is a military installation but it’s not filled with people with guns.
As is true of most military bases, the only people that are normally armed are Army civilian police officers and sentries (gate guards, etc.).
The shooter went to the Soldier Readiness Processing Center, a medical facility where personnel either embarking on or returning from deployment are checked over. There were no armed soldiers at the Center. Unarmed soldiers rushed the shooter and all were shot, two fatally.
The shooter continued shooting soldiers. He ignored civilians in the area.
It wasn’t until civilian police officers arrived on-scene and confronted the shooter that he was taken down.
The only reason you can’t buy the latest military small arms is the Hughes Amendment to the Firearm Owners Protection Act of 1986. The Hughes Amendment closed the federal registry, which is where all machine guns have to be registered in order to be transferable. A rifle, such as an M16, that was registered prior to May 19, 1986 is completely legal to own. So are bazookas, mortars are other small arms. You can also own tanks and artillery but it’s been years since the Department of Defense did anything with surplus or obsolete armor or artillery other than sell/give it to another country or destroy it.
The phrase “well-regulated” means organized and disciplined. It has nothing to do with laws governing arms. Furthermore, for the past thousand years, militias have been composed of private citizens armed with personally owned weapons. This was also true of the pre-empire Roman Republic.
Under every federal militia law that has been enacted since 1792, the United States Militia has been composed of able-bodied men at least 18 years old and less than 45 years old. That’s still true today. The National Guard is actually a reserve unit of the United States Army that is also available for civil duties. It is only one component of the U.S. Militia and the only one that is funded or equipped by the government.
Passion is a very poor substitute for knowledge when trying to make a reasoned argument.