Because I usually do not carry cocked and locked. I much prefer to carry with a live round in the chamber and the hammer down.
Why are you surprised that I carry that way?
Because if you drop the gun on the hammer....
A 1911 has three safeties: The trigger, the safety on the backstrap and the thumb safety.
Also you can thumb the sdafety off easier and quicker than you can cock the hammer.
It takes some getting used to, but cocked and locked is the most safe.