But it's not up to you(Or the police) to decide what should and shouldn't be filmed, right ? He's well with his rights to film the arrest, now you can disagree that it wasn't of huge importance but that clearly wasn't the argument the police were making, they simply wanted him to stop the recording and go home.
Alternatively how about the officers let the person continue to film at a safe distance ? Rather than breaking the social distance they are suppose to be enforcing ? Which would have resulted in a safe outcome for both the officers and the journalist.
It was the officers who broke the socially distancing in order to try to stop him filming(In fact it seems they got out of their van to do this
). There was no need for them to do this as the guy filmed hadn't broken any laws.