First, this isn't meant to be an attack on you. Allow me to quote you and say that you seem to know what your animals would/wouldn't do for you. I also have a fair idea of what to expect from mine. I, myself, have seen my two dogs engage in all sorts of dominance behaviours, such as the humping you mention. They are dogs. But I have also seen them come to the aid of each other and show a great deal of concern when someone, especially a child, is upset or in pain. Of course, this could just be my interpretation of a simple random act of a "dumb" animal. Whatever.
There are countless stories of dogs, and even cats, coming to the aid of humans and, in some cases, other animals. It would seem that these capacities had been developed. Was it the environment or was it genetic? I don't know. But I don't think it was an accident of mere statistical probability. It appears to be a deliberate act that, if performed by a human, would be considered heroic or at the very least pro-social.
And as to loyalty being a human trait, I wouldn't count on people to do the right thing either. We have parents who celebrate their children's short career as suicide bombers or who beat their children or drown them or leave them in a hot car to die. And don't for get the famous case of Kitty Genovese, who was stabbed to death in an attack that lasted over a half an hour while 38 people listened, but no one called for help until 20 minutes after she died. The police arrived 2 minutes later.
Do these acts of the few negate the capacity or potential for human good? We still find humans enslaving other humans. Even human cannibalism is not unheard of, but hey, protein is protein. We are all strangers in a strange land.
Because a level of prosocial behaviour hasn't manifest itself or been developed doesn't negate its potential. Social behaviours, such as loyalty, are traits that intelligent mammals do seem to be capable of. Not just humans, but many other mammals. Perhaps it is that the mammalian brain (as opposed to the reptillian brain) is wired for this behaviour and that genetics and the environment develop it. It certainly provides evolutionary advantages.
My appologies if you are/were offended.
I remember reading that when someone actually went to go interview those people, most of them thought that with so many people around, someone must have already called the police. So it wasn't inhumanity, it was buck-passing.
If you were going to be consistent, you'd have to oppose eating any mammals. Another argument I really don't get is the "it violates trust" argument. If dogs in general truested humans in general, what good would guard dogs be?