There are people here who may only have one or two shots a year at a deer, any deer. Why should they pass on an opportunity to harvest a deer legally simply because someone else thinks it "isn't right"?
Beats me. I can only tell you why I didn't shoot--lack of fun. The one ethical point that does come up the most here is whether it's fair to the deer to shoot in such a situtation--in other words, if the deer had a chance to employ its defenses to get out of danger and was beaten at it by the hunter through his hunting skills.
There are situations where that isn't the case and its not right to shoot if we're going to be considered sportsmen. A game animal is entitled to use its natural defenses or we're abusing the gift that they are.