Obviously the hunter. An ethical hunter has a responsibility to be proficient with his weapon so as to assure a quick, clean, humane kill. It's not the best analogy though because a 12 gauge slug has a much better chance of dropping a deer regardless of shot placement.I know people that can’t get a clean kill with a 12ga slug; does that make the caliber unethical?
Or the hunter?
In an ideal world where all hunters are somehow magically required to be ethical, I completely agree with you. If you have the skill, you should be able to harvest deer with whatever you see fit. I mean we are allowed to use an atlatl during the "Alternative methods" portion of the season and I have serious doubt that many people are proficient with one of those. So I suppose really I should rethink my position on either that law or the law that allows people to use atlatls. Hell, bow hunting for that matter. I spent/spend a lot of time practicing with a bow so that I can be sure to make clean shots. A lot more time than it takes to get accurate with an AR and a red dot.
So I guess I see your point.