Semi problomatic
My understanding of the military using .223 on people, is not that it kills efficiently, and not that it is a close combat "Man stopper", but that it is:
light weight (compared to 30-06 and 7.62 NATO)
compact - soldiers can carry larger quantities in smaller magazines
less recoil - muzzle doesn't climb as much during full auto
economical - less lead, less brass,ammo production costs are less
wounds without killing - requires 2 uninjured combatants to leave the battlefield to take care of each wounded. Then, many initially wounded die anyway, but created a burden on enemy resources, depleting medical supplies.
I'm sure that the Small Arms Weapons Board, at Fort Benning Georgia, home of the Infantry took ALL of these factors into consideration in the pre-Vietnam era. The 2 tours I pulled in RVN proved they were right about the design, in all aspects.
The .223 was not designed for whitetail hunting. It is what it is - an infantry round - in the original FMJ configuration.