Does your boss hit you when your less productive at work?
I believe that whipping children is quite bad and, on its face, substantially worse than allowing children to watch videos of other children happily playing with toys.
Children, especially very young children, cry over dumb things; it's normal and expected and beating them for it is both cruel and (as mountains of evidence have shown) counterproductive developmentally.
That's not to say parents should give in to tantrums, they should not. But there is a vast space between giving in to tantrums and beating children for them, and it's somewhere in that space that good parenting lies.
My pet theory is that since in school environments physical punishment was distributed "equally", that's not as bad.
I really wonder how far back corporal punishment dates in the west, and whether brilliant people like Einstein ever received physical punishment.
It doesn't take a scientific study to realize that teaching children not to be violent by punishing them with violence is confusing. Especially to a small child.