If the Jewish gentleman wound up being attacked by the protesters, what would have happened to an individual cop who did nothing to try and avoid that situation?
I don’t totally disagree with you. The Jewish guy was in a bit of danger. Muslims can be violent. And Muslim mobs even more so.
So, yes. I think the cop had a duty to talk to the Jewish guy, and warn him. But threaten to arrest him? Nope, that’s crossing the line. That’s the cop blaming the possible victim for any possible trouble.
As a rough analogy, consider a guy wearing an expensive watch. And he’s taking a stroll in a bad part of town. A beat cop sees him. Should the cop warn him? Yes. Should the cop threaten to arrest him if he doesn’t turn around? I’d say no.
Better that the cop keep extra alert for criminals while that (maybe stupid) watch guy is on his walk.