In the same chapter, St Augustine compares the brutality of flogging and abusing adults as punishment with the brutality of corporal punishment of children, and the effect of pain and intense fear it has on them:
"Is there anyone, O Lord, with a spirit so great, who cleaves to thee with such steadfast affection (or is there even a kind of obtuseness that has the same effect)--is there any man who, by cleaving devoutly to thee, is endowed with so great a courage that he can regard indifferently those racks and hooks and other torture weapons from which men throughout the world pray so fervently to be spared; and can they scorn those who so greatly fear these torments, just as my parents were amused at the torments with which our teachers punished us boys? For we were no less afraid of our pains, nor did we beseech thee less to escape them."
It's perspective and how it's implemented. Should kids be punished? Yes, if its necessary. Should they be beaten? No. Beating isn't done for correction with love. Corporal punishment, when done correctly, is.
I once knew a dog breeder who, when the puppies were first let out of the house, would take each one to the paved road and rub their paw pads until they were raw. Most people would be horrified at this, as I was until she explained why. She had lost many dogs on the road by getting run over. She loved each one as a family member. Since she started the paw rub, none of them ever went out into the road even if they got out of the house on their own.
I don't suggest rubbing kids feet on the road, but a good old fashioned spanking does wonders to keep them out of the street. Not a beating out of anger, but a corrective action done for the sake of the child.
Spanking is not abuse. Beating them up is. I wish people would learn the difference.