The child knows what he or she is doing. Such a person may learn not to behave in a certain unacceptable manner, but the root cause can still remain. As I mentioned above, the connection between slaughterhouse worker and domestic violence is a perfect example. Violent behavior in one area of a person's life usually expands itself to other areas, too. This may be the case sometimes, but usually the reason is fear in general, with the victim believing that the violence directed toward them is partly or wholly their own fault.
Domestic violence is a form of intimidation.
The killing or hurting of a loved animal companion can also be a form of abusing the person. And since abusers are sadistic, they usually will do anything they can to hurt the other person. Yes, but only because it removes the person from society. It still doesn't solve the real root problem of the way we sanitize violence in our society. The problem is that many people in positions of responsibility are also abusers, even if only in socially acceptable areas.