Some people will argue it's the right of the parent to discipline their children as they see fit. Maybe the child did something to put himself in danger and it warranted a swift and harsh response. On the other hand, the mother may be an irrational tyrant who takes out all her anger and insecurities on her innocent and helpless child.
Others will argue it's your duty to stop obvious child abuse and you should intervene or call the police and report the mother.
We see these two opposite reactions all the time in this forum. 'Leave the parent alone. It's none of your business how she disciplines her children.' 'The parent is a monster and the child should be removed immediately.'
Is it ok to stand back while a parent beats a child in front of you? Is that accepting the banality of evil? Should you intervene? When is it right or wrong to intervene or not intervene?
If they child is later beaten to death because you didn't intervene did you accept the banality of evil? If the child is taken from the parent and the child later suffers even worse abuse at the hands foster parents are you guilty of over-reacting and causing the suffering or death of the child?
What we get is Monday-morning quarterbacks telling us why we should have responded differently.
There is a big difference between spanking a child and beating a child. Normal people know it when they see it.
Parents discipline and spank a child out of love and the need for correction (so the child will learn right from wrong).
Sick people beat their child.