We cannot define ethics for each other.

I'd like to add that I'm pretty sure that my sks (7.62X39) with approx 1500 ft lbs of energy, kills deer faster (more ethically) than my 30-06 with approx 3000 ft lbs of energy. Sometimes there is no exit wounds on deer shot with the sks, which means the deer got the luxury of feeling all1500 lbs. My 30-06 on the other hand, when not meeting much resistance may pass through with minimal expansion. Possibly dumping 2700 ft lbs into the hillside? Shoot what you shoot straight. If you can kill a deer with an arrow, you can kill them with just about any rifle and that would include some air rifles!