I think you misunderstood. Some of the most dominant dogs are not the ones that are the most overtly aggressive. For example, Nikon turns on a very high level of aggression when doing civil work but in many areas he is not as confident as the other dogs and of all the dogs in our club, he is probably the most handler sensitive. He's not a dominant dog, but he will bite and bite for real. The dominant dogs will push the envelop in every aspect, every phase. Tracking, obedience...doesn't matter. Give them an inch and they take a mile. Typically a dog that is handler aggressive is so because he has been mis-handled, not because he is unstable. For example, I'm sure you may have seen even pet dogs that have been nagged and overly corrected so often that they get to a point and literally snap. In SchH, this combination with a dog that is already dominant and probably has some sharpness to him as well can lead to handler-aggression incidents. Dominant dogs will not stand for handler mistakes. I know for a fact that there are street dogs (working police dog) with long histories of great work in their departments that have drawn blood from their handlers. It takes a certain dog to put their lives on the line to protect us and have a successful record of street bites. Sometimes mistakes are made in handling, or the dog simply redirects. It's not that these dogs are more aggressive or quicker to bite, but they are unforgiving of mis-handling or inappropriate corrections. A dog not as dominant might sulk, shut down, recover, or just not notice. The dominant dog knows when the handler or helper is out of line and will let you know. The term "handler-aggressive" is not used to label an unsound, nervy dog that snaps on his handler, but a civil dog that understands his work enough to make it clear when the humans are not doing it right.
Of my three dogs, Kenya is ironically the most dominant. The boys rarely challenge her, and she will correct them when they are out of line, not abiding by the rules (if her interpretation of the rules fits with my rules, then I don't step in). However she is not aggressive, passed the CGC, TT, and multiple therapy dog evaluations, no bite history and won't tug with me over raw meat let alone do formal bitework.
She is also a good example that dominance is relative. When it comes to dog-human interaction she's somewhat neurotic. With other dogs she is the leader of the pack, and she doesn't have to push anyone around to keep that status. It's like they just *know*. She only interacts with dogs on her own terms and is usually content to stay off to the side chewing a bone. But if she does want to play, the other dogs let her take the lead and take her corrections when things are on the verge of escalating.
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