One of the first things you are taught as a cameraman is to establish the kill and not show needless suffering of the animal. Those quick pans back to the hunter are done so the animal isn't shown thrashing on the ground. From an editing standpoint I would take that and the first quick reaction from the hunter and then edit in the later conversation that was filmed from the same position and perspective after the finishing shots were made. A dither dissolve can make the transition from the first pan away to the later taped interview very seamless.

If someone were to carry on and hoot and holler while a deer is writhing on the ground I would have the same reaction as you and be disgusted with those "hunters" but in most cases things are being handled the proper way without showing the gruesome follow ups.

I do agree that a moment of explanation of what happened would be appropriate in a lot of cases to fill the audience in on what they assume happened, but sometimes egos won't allow for that. Other times it is a conscious decision not to mention it because we are under the microscope and don't want to provide any fodder for our detractors. I'm of the opinion that telling the whole story, good or bad, is the best policy though.