It's tough to examine that claim without stating names. I can tell you that my fiancee had that issue and I'm fairly certain she was never hit, based on her report and her families reports, and my own observations. Two of my roomates who I trained, the same-they and their families denied ever engaging in corporal punishment, all lovely people whom I believe, and they denied ever being in a fight. Flinched when I started teaching them martial arts. People at dojos that I've trained in had flinching reaction, despite their own reports of not being hit and/or in a fight, although I can't give a number and that's obviously less reliable since I don't have any collateral for that..but I have no reason to disbelieve them. I had my own flinching problem which got solved by fighting more as well. Sorry, that's my own assumption that he had been abused. For clarification, physical child abuse is defined as "Physical child abuse is physical injury inflicted upon the child with cruel and/or malicious intent. Physical abuse can be the result of punching, beating, kicking, biting, burning, shaking, or otherwise harming a child physically.", according to medicine.net, which I feel can be transferred to animals as a good definition for physical animal abuse. I personally would add in something about a position of power for the abuse if I were to generalize that statement (a 3 year old could hit a 10 year old meaning to hurt him, but I wouldn't consider that abuse for instance). So I made an assumption that a dog that reacted to any hand coming near him as a possible hit and at least sometimes bit that hand had been physically injured with cruel/malicious intent. That intent may have not been there I suppose, he could have attacked someone who was just defending him/herself. The rest of my statement still stands.