"Because in law you are forbidden from striking another adult, and from physically chastising your pets, but somehow there is a loophole around the fact that you can physically chastise your child."
Is Ms Atkinson aware that the law also forbids you to imprison another adult in their bedroom, restrict their movements to the "naughty step", impose curfews on them, and so on?
If the ideas behind the absurd arguments of the brigade who want to criminalise smacking were followed through, then it would make parenting itself illegal. When parental powers are reduced, who takes up the slack? Answer: highly paid state officers like "children's commissioner" Ms Atkinson.
We presume that she gets up to other things too, but, as she spends her time arguing that ordinary parenting should be criminalised, the state rewards Ms Atkinson with over £140,000 of taxpayers' money every year (http://media.education.gov.uk/assets/files/csv/occ%20senior%20staff%20data%20march%202011.csv).