I am a first responder. I would not allow someone to do this within my purview. It is assault. If you want to calmly tell someone your point of view, you can do that. If you want to express how sad you are, go for it. If you use a threatening tone as this person did, if you pursue them after they have calmly asked you to leave them alone, you are assaulting them.
If it happened somewhere outside of my zone of authority I might feel the need to protect her in a more physical manner. Who knows?