Hunting is more of a game than what you realize.Why do you think people spend countless hours scouting,setting up game cams,planting food plots,etc? Because they want to win the game.I also think it'd be more thrilling to down an animal at some of those ranges than shoot a buck you know will be stepping into that food plot at 4:23pm every afternoon.
If you're well-practiced at those ranges,there's absolutely nothing unethical about long range hunting