What the Army does is rarely key in what we should do; but I concede the outdated point. The military sidearm is rarely a first-line weapon. I know for a fact that guys loaded their pistols after leaving to go out on patrol in Vietnam, even though loaded chambers were not allowed on bases. For the cops and FBI agents that carried 1911s, how do you suppose they carried? Same as the military rules for bases? No. Loaded; cocked and locked.
Regardless, modern handgun technique is to carry your handgun loaded in a manner that makes it safe to do so (holster, knowledge, etc.) As such, the 1911 should be carried loaded and cocked with the safety on. Modern 1911s are even safer in this condition than their predecessors.
Some people (this is not directed at anyone here) are alarmed at seeing the cocked hammer. They honestly need to learn how to just get over it. A loaded Glock is 60% cocked. A loaded Springfield Armory XD is fully cocked. A loaded Walther PPQ is fully cocked. You just don't see the striker, and out of sight is out of mind.
I still hear people on the other side of a room (in a gun store, no less, sometimes) whisper to each other that my hammer is cocked. It's amusing, but telling of a new generation that grew up with different guns.
If someone personally thinks they should carry their 1911 without a round in the chamber, then they should realize that they should carry their Glock, XD, PPQ, or even their DA auto in the same way. But that is a decision each person should make for themselves. Just remember that it takes two hands to load a pistol in any kind of quick and/or safe manner. And defending yourself often involves extremely close quarters and wanting a hand available to do something else, assuming you had both hands free to start with.
I strongly recommend a holster and training that makes you comfortable with carrying a modern 1911 in Condition 1, as it is (present tense) designed.
And yes, the thumb safety is still superfluous; but we've worked it into the modern technique as a traditional feature of the platform. It adds no time to the deployment.