As a lifetime dog owner and obscene over the top embracer of all things canine, I would shoot a dog over a human being. Growing up, I always said it would be easier to kill a human than a dog because of my love for dogs and mistrust of humans, but life has put me in another spot during my adult years. Yes, as an adult I have seen the good of humans and thus have faith in them.
I do not subscribe to believing people are as rotten as others suggest, but then again I feel like I've been exposed to a lot of "people love" in a small growing town I live in, as ghee as that sounds. Having raised 3 daughters and joined in force with other families the trials and tribulations of raising a family along with the benefits of watching progress in a child, I would be haunted by the fact that the person I shot could be a parent, caregiver or child which would destroy the lives of many others, both family and friends. Killing a dog would not have the same adverse effects of a human killing. Depression, Suicide, PTSD, Anger and all things bad would blanket a circle of friends and family based on the unnecessary death of a single human. The dog death (I've buried three 100+ lb dogs on my own property) results in personal hurt that goes away incrementally and often replaced with more dogs for future love. Don't get me wrong, I cry and cry often for the months/years following many of my dogs passings, but I'd say I've had more issues getting over my mothers death 10 years ago than 4 dogs that have died since. My past/current dogs are the only living things in my house that I never yell at or punish because I have an inherent belief that dogs can not do any bad. My kids point that out to me often, but alas I gotta go with the person.
I think the core of it for me is that having children of my own, in no way will I shoot a person over a dog.