The difficulty in a justice system is the problem of people not guilty of things going to prison. However once we realize beyond a shadow of a doubt (like in this case) we should completely separate them from society. This person harmed a child. Lied about. Taunted the father of said child afterwards.
Why do you I feel that you would be singing a different tune if it was a man who attacked the child, got a light sentence and then taunted his ex-spouse?