I know you're not supposed to discuss ethics on this forum but I think you are getting into an area where you need to discuss just that. I agree it is hard to argue and possibly set limits for other people based on how ethical their choice of caliber, max range, minimum impact velocity/KE. I'm the end though we as hunters (particularly if you hope to see hunting continue for your kids) owe it to the animal to only take shots that we are highly confident that we will hit vitals and quickly kill an animal. For me the thought of not practicing shooting a particular range. Angle or most importantly a horrible shooting position and going off a computer model based on a few shots from a bench at short range is totally unethical.
Go climb a 40 degree shale slope and try to get a comfortable set up between the manzanita and connect first round on a 500 yard shot. Your pounding heart and lack of steadiness/comfort will become very apparent. Add in some unkown cross canyon winds you've never experienced and it only makes it worse.
Without real world practice the only way I can see this happening is with a coach. A guide using his equipment who regularly shoots those conditions. If the guide can get the shooter in a very solid/comfortable position to where all they need to think about is the trigger squeeze then it's possible.