The answer to your question is this: DoD and CENTCOM Policy, and shoulder holsters.
Military policy on base/FOB/COP or wherever is that all firearms will be either unloaded at all times, or will not have a round in the chamber unless you are outside the wire. I understand that his cuts down on the number of negligent discharges, but it also restricts your ability to return fire in self defense. It's time for this policy to change, in order to reflect the non-linear state of the modern battlefield. Let us put a full magazine in our pistols, and a round down the tube. There's a safety lever there for a reason; let us take advantage of it.
I also take issue with the way so many staff and support personnel carry their sidearms in godawful, cheaply made shoulder holster. Most of these rancid things are designed more for convenience, than for actually employing your sidearm in defense of your own life. It leads to a culture of complacency in which airmen and soldiers lose focus of the fact that there are people out there trying to kill them. If you absolutely must have a shoulder holster, then we need to issue something less restricting. Blackhawk makes a very high quality shoulder rig for their Serpa line of quick release retention holster; maybe its time for that to become standard issue to anyone carrying an M9. Otherwise, get a belt and a standard holster and carry like you mean it.
Simply put, its time for a change.