MM,
What you are saying is pretty much "correct". The difference is point of view.
The fact that a shot was made at that range leading to the harvesting of an elk cannot be denied. Guessing that it is hard for an elk to pretend to get gutted and skinned.
The ballistic facts generated from a computer programs are also "accurate". However, bubble bees do fly and we all pay income tax.
What you are missing is that a 300gr bullet arriving even at 1000fps is lethal...period. The fact that it has this many foot lbs is irrelevant. The bullet will penetrate through the chest cavity disrupting the internal organs leaving a lot of skinning and packing. So will a broadhead arrow at 75yds (LR by bow standards).
Yes, the bullet is falling like a rock and can drift a lot in a cross wind (if there was one). That is why we use the rangefinding equipment that we do. I would also suppose that a windage shot or two was made to confirm the wind/elevation at the target before the elk was engaged. I will also suppose that the rifle, shooter and the "bench" were up to the task. I really doubt this was a Hail Mary type of shot.
With all this said, do I condone most hunters from doing this type of shooting. Absolutely not!!! I believe that those on the board that do LR hunting invest enormous amounts of time, money and energy to perfect their art. I know I do.
I also believe that they watch a lot of game walk then take a risky shot. Ethical hunting is ethical hunting. No matter how far away the target is, if it is above the ability of the hunter or the equipment/situation, don't pull the trigger.
Did you know that once a high BC bullet goes subsonic, it slows down very little? It is dropping very quickly but essentially has the same "energy" over an enormous range. Look how effective the blackpowder cartridges were at long ranges. Talk about heavy bullets/slow muzzle vel. So yes, a 300gr bullet out of a 338win mag will be lethal at 2100yds if you have the equipment and skill to get the bullet into the boiler room. Would this my best choice for a LR load...nope.
Enjoy,
Jerry