I've hunted for over thirty years. Everything from upland small game -- rabbits, squirrels, birds, to deer. No waterfowl, no bear.
And while, yes, it is "the responsible thing to do" for a "potential target" to do everything in reason to ensure that he is visible as a human (hence, the near-universal "hunter-orange" clothing laws), the fact remains, that if I pull the trigger on you, I am to blame, period.
It's no different from the ("classic") "rear-end accident."
In fact, when my body was ruined in a "rear-ender", the ***** who flew into me while I was stopped behind another car at the intersection got into a pissing match with the cop, demanding that he ticket ME, because, as she put it, "It was HIS fault!"
The cop finally threw up his hands and said OK, fine -- what should I ticket him for? (This little adventure was related to me after the fact by one of the numerous witnesses.)
Suffice it to say she got the ticket and I nearly bought the farm.
Yeah, I should have had "working brake lights", to warn her that I was stopping. (And I did!) But regardless, it was HER responsiblity to "maintain control over her vehicle".
When you point the muzzle of your gun at something, and you pull the trigger, then you own the results of whatever happens when the load meets the meat.
That is, unless you are of sufficient "rank" to not have to worry about such trivialities.
It doesn't seem, from the story, that the Vice-President is trying to shirk responsibility for the shooting.
This isn't a rank issue. It happens. It's probably just an accident. And it has absolutely nothing to do with your traffic accident, you can't analogize to brake lights or rear-end collisions. Customs and practices in the field are not Uniform Rules of the Road, and there isn't any legal liability issue here.