Mixed opinions on this subject and subsequent story.
Anyone can fling an arrow (or bullet) and make a poor shot, then want to claim a big buck is "theirs", even though they can't find it again. It is fair game for another hunter.
But, if I saw it happen, and watched where it went, I would be the guy that tried to get the hunter's attention and "walk the hunter in" and helped get another attempt at the buck. Not keep the location to myself of asked and then go after the buck when the hunter gave up.
But...if I had been actively hunting the buck for days or weeks myself, and saw the event, but the buck was not mortally injured and escaped, it might be a different story. You had your chance, but blew it. My turn now.
I have had my share of people trying to obviously beat me to an animal, or take a VERY unrealistic shot in an attempt to either get the animal before I could, or scare it away so I would not get an opportunity at it. Believe me, in those cases, if they made a poor shot and could not locate the animal, and I could, I would be a lot less inclined to help them find it and just wait them out.
Call me an asshole if you want, but there are two sides to every story like this.
Of course the first hunter wanted to find the buck he hit poorly and could not recover, but got irritated when someone would not help him locate an animal he was incapable of doing so himself.
Of course the guide wanted his paying client to get a crack at the buck, even if it was previously poorly hit.