Legitimate where? As far as I know, in the state of Israel, as well as most other countries and the United Nation Convention on the Rights of the Child, bodily harm (grievous or otherwise) as well as any form of physical or mental violence against children is prohibited.

There's a difference between legal and legitimate.
AFAIK the vast majority of parents in Israel use some sort of force against their children from time to time. That makes it legitimate in the eyes of the public, even though it might be illegal.

and we all know how seriously the world regards the U.N.

so much for a low crime rate...