I agree, pulling the trigger on an empty chamber is redundant and calls into question the entire clearing process, but in Army logic, it is the final check. If the person clearing the weapon has a brain fart and doesn't do the sequence correctly, the pull of the trigger on a supposed empty weapon is the final means to guarantee that the weapon doesn't leave the clearing station loaded. You would think that grown ass men can accomplish a simple task such as this but alas, there are mere mortals who are incapable. Education and rank have no bearing.
People become complacent with guns the longer they are around them. the person who lowers a loaded firearm from a tree stand is a willing participant in the theory and practice of Darwinism.
The first rule of firearms safety is "all guns are loaded" . Not "treat all guns as if they are loaded". that immediately allows the brain to think it may be unloaded and you don't have to be as careful. By considering all guns loaded, you treat them as loaded firearms until such time that you can clear them and make them safe. even then you still keep your finger out of the trigger guard and keep the muzzle pointed in a safe direction.
