Prmit this example :
A four year old son was at a day care facility with about 25 other small children.
One bully in their midst was pushing a little girl around. She did not like that.
The four year old son punched the bully in the nose, simply. Flat out. No discussion.
The bully stopped. The little girl and everyone else around was happy. It was good.
It was right and just.
(and likely at least a deterrent for a day or longer, so the bully did not do it again)....
Pinching the bullies arm would have resulted in more bullying(probably), not in stopping the bully.
Leaving the bully without doing anything may have led to harm to the little girl. Some injury perhaps, physical or mental or other.
So, what was actually done was right, was approved of by the adults present, was approved of and appreciated by the little children present , and good clean playtime without the stress of the bullying was accomplished simply with no injuries and no injustice being permitted.