There were a bunch of protestors that they were pushing back. I’m guessing they gave the protestors their 4 or 5 warnings to disperse and then when they didn’t the cops pushed forward.
The old guy comes up to the police and confronts them, and is toughing them.
They can’t stop to arrest the guy as they don’t have the protestors controlled yet. The cop that did tried to help the guy got told to leave him and stay in the line to push the protestors back. The cop that told him got on his radio, and I imagine it was to call in aid for the old guy - but obviously just a presumption.
Their job was to control the situation first, and then help the old guy. It would be interesting to know how long it took help to get to him. I imagine not too long.
I once had a member of LE give me his take on the use of force: that the force should be commensurate with the threat. I think my acquaintance would argue that the threat posed by the geezer poking the cop with the phone did not warrant the geezer being sent to the ground. If unable to arrest, brush aside, ignore, threaten to call the perp’s wife.