Whether the criminal justice system should be involved depends on the degree and nature of the child abuse.
But any parent who can't figure out how to discipline a child without physical violence is either just ignorant of the more effective child rearing techniques and can benefit from education about parenting, or is lacking the necessary brain capacity needed to comprehend the better suited techniques.
The fact that one's parents were equally ignorant or suffering from brain functionality is not an excuse, it is just a possible source of the problem.