The trouble with ethical arguments is that everyone has his own idea of what's right and what's wrong and those beliefs can be strongly held. I can no more change your core beliefs than you can mine. Debate however can be a good way of self examining our personal beliefs to determine if they are balanced or askew, note I did not say right or wrong.
An ethical hunter is one who assumes he has a reasonable expectation of making a successful shot, the length of the shot does not come into question, only the question of his ability under the conditions of the moment. Does his health and physical condition allow him to make a steady shot after a few hours of arduous hunting? In some locations, fall time weather can be just awful, and if you hunt in such weather it is unlikely you will be successful in making a shot of much over 100 yards due to wind, blowing snow, fog, freezing rain, whatever. Sometimes the wind is so strong the only position that is useful is prone, but if vegetation is in the way, you have to get closer, or move back to the top of the hill for a clear view. Someone who attempts an off-hand shot under such conditions has a low chance of success, so the question of taking that relatively close shot becomes an ethical problem; yet the range is easily within the ability of most competent riflemen under better conditions.
How often do we hear that when a deer bolts at the shot, the proper thing to do is to sit and have a smoke or two while the animal lays up and stiffens? The trouble is that the animal suffers for the half an hour you wait, and continues to suffer if you are unsuccessful in tracking him. Is that ethical? On the other hand, if you follow up immediately after the shot, the deer could continue to travel for quite some time before it collapses from blood loss. Is that ethical? Yet once we press the trigger and our target disappears, it is clearly unethical to do nothing, so we must choose the lessor of the evils which ever choice that is.
In some localities hunting big game with dogs is perfectly fine, other places not so much. Some people like ranch hunting, others call it a canned hunt. In some places shooting over bait is fine, in other places, no. Some folks disapprove of trophy hunting, others thrive on it. Some folks prefer to hunt dangerous game as they would any other big game animal, shooting it while it is in a relaxed undisturbed condition, while others prefer to get in close, confront their quarry, and if possible instigate a charge. Behind all of this is what we call ethics, the challenge is to find the right balance. But we must also accept that what is right for us might not be for others, and what is right for others might not work for us.