"In two strides I was behind the schoolgirl. I reached up, seized her ponytail at the roots and gave it a sharp downward yank. Her head snapped back. In a voice I didn’t recognise I snarled, “Give it a rest, darling.” She twisted to look behind her. Her eyes were bulging, her mouth agape. I let go and she bolted away to her friends. The three of them set off at a run. Their white ribbons went bobbing through the crow…
"If you switch a 70 year old woman, to a 70 year old man" Or pretty much anybody other than an elderly white woman (in a "western" country). Anyway, I don't think the physical violence was necessary but I do admire her intervention on behalf of a stranger against an obnoxious (probably racist) act.
Over-reaction. The lesson shown here to kids and those watching, if you feel others are being threatened, physically strike back. There is no immediate threat, words would have done the job.