Im going to try and address as many of the points made as I can. To be clear, this is more of a question of efficacy vs ethics. All I am concered with, for the purposes of this thought experiment, is killing and recovering animals. Suffering is not a part of the criteria. Lets assume we shoot supressed and the animal is unconcerned with the report of the muzzle blast.
1. If you speak to a lot of folks who do deer control in suburban areas they all shoot for the head/neck so the kill is instantanious. The animal drops right away with no blood trail. No one wants deer blood sprayed all over their nice neighborhood in the gaited communities or on the 18th hole at the country club. Some of these varmit control guys kill HUNDREDS of deer this way. So at the very least, there is a lot of precident to suggest its not an inefficient way to kill. For some reason people have NO issue shooting coyotes, ground hogs, feral pigs, doe deer, and other varmit in the head, why does it matter for a mature male deer? This may be contraversal, but I think the trophy hunter in us looks at those antlers and says to ourselved "what if i accidentaly hit those?"
2. I posted this in Long Range Hunting becasue it is unbelievably common for people to shoot CNS at close range. Im not at all curious as to the efficacy of that. However, at long range, bullets slow down, wind becomes a factor and animals have time to move from when the bullet cracks to till impact.
3. Lower jaw getting shot off. I agree, it looks awfuly grousome, but how is that any worse than being gut shot? either way, the animal dies a slow painful death of starvation. On the flip side, if you hit the CNS, the death is almost instantanious. MANY time ive seen western animals get shot 2+ times. Cant imagine that is a better way to go than having the lights shut out. To those who have seen it happen, how certain are you that the person was aiming for the head and hit the jaw and it wasnt a bad vitals shot? I also couldent care less about what the non-hunting public thinks about seeing a deer with its jaw shot off. They'll think the same about deer and elk skulls in the beds of trucks and thats not stopping any time soon.
4. The kill box size - if someone could provide for measurments for the total square inches of vitals vs the total square inches of neck and brain on a deer that would be super helpful. I may be willing to concede this point. I do think the area of CNS in the neck is MUCH larger than people realize. impacts anywhere near the spine will cause a shut off, damage to any artery will cause the animal to bleed out in seconds.
@VernAK puts out some awesome anecdotal evidence. Moose are probably a great exception. Giant snouts, giant meaty necks, giant vitals.
However, it wouldent change the argument that the margin for wounding the animal is much higher on a center mass shot.
5. Great points about heads moving more than bodies. but once again, if the animal moves its body from when you break the shot to impact, on a vitals shot, you are more likely to wound. if the animal moves its head on a head shot, you are more likely to have a clean miss.
6. severed trachea - I have a hard time believing that an animal shot in the trachea would get JUST the trachea damaged and not the CNS. If it did, i would be willing to bet that the trachea would heal up just fine and the animal would live.
7. small caliber - i really dont care to debate this particular topic as it is adressed over and over again in this LRH sub-forum. small caliber rifles are easier to shoot plain and simple. However, the effects of wind drift are an interesting take.