Fight or Flight is a very human response to high stress, high tension scenarios.
Probably “take it easy, I’m the police” was too much provocation for the father at that juncture.
I don’t buy the fight or flight rationale. Neither I nor my husband would respond in such a way in an accident. I doubt seriously that any of my neighbors or people living in my town would act that way.
This father should have been focused on the needs of his child, not on delivering a beat down to the motorcycle rider.
The fact that his first response was violent says a lot about the culture of violence that permeates urban areas and the decay of civil society.