This is called green status for weapons. Unloaded. Amber status is common for smaller FOBs and outposts. Magazine loaded, but no rounds chambered. Red status is pretty much only for patrols or direct action. Locked and loaded.
At a larger base, they were no doubt on green status. I don’t know if these nine were being complacent or not, but even a trained shooter can be too distracted to load quickly and correctly while being ambushed at close range.
The NINE were not “ambushed”. They were lined up and shot execution style. They were NOT allowed firearms on or near their person. Obviously nobody asked the Afghan pilot if he was obeying the rules because he simply walked back to his office and retrieved a loaded handgun.