Nope. You're wrong about a lot here. "Critters" die about as fast from bows as from guns. A good broadhead through the right spots (placement) is as lethal and about as fast as a bullet. Arrows are also absolutely lethal from hits to places no bullet would work at all (femoral artery shot for one).
You don't help your relativistic ethics much when you are just wrong.
Ethics may be debatable, but debates do not end in ties very often. One side usually wins. "Debatable" does not mean there is no right or wrong, and disagreement does not mean both sides are right. One can be absolutely wrong in terms of ethics, so it is possible that there are ethical and non-ethical ways to hunt.
For example, I bet we could get a profound majority to agree that it is "not proper hunting ethics" to pay someone to allow you to walk up to a cage and shoot an animal inside it. The whole canned hunt argument is not about anything more than "how big a cage does it take to make it ethical". Everyone knows that if the cage is too small, it just isn't right.
It is not enough that hunters use the "whatever you want, as long as it's legal, is OK because we must hang together and not criticize hunters" line. I think we MUST become critical of unethical hunting, or some practices will be used by the anti-hunters as easy proof that we are
not ethical.
Hunters must have these discussions and bring them to a conclusion about what hunting ethics are, and our ethics must be "debatable" in the sense that we must be able to defend them with reason and logic. If we defend hunting practices that the vast majority of people would condemn as "unethical", we will only hurt hunting in the long run. Hunting must be "fair chase".
So this argument is not about anything more than "how far is too far to snipe animals without most people knowing full well that it wasn't fair chase at all."
I think that it isn't fair chase if you are not at least on the same quarter section as your target. I bet most people would agree with that.
So what is the "distance we will tolerate and defend"? Don't forget you may have to debate it, so think it through.