So the press helicopter is supposed to figure out that the “cop” is actually the killer, turn around, fly back to an airport, pick up a police/military sniper who just happens to be armed and ready, fly back to the island, reacquire the “cop” target (and not hitting any other cops that might also be there via boat), and take him out from the sky (the newly acquired sniper being an expert at shooting from a helicopter also). I’m sure that’s an easy task done in a minute or two. /sarcasm.
Reactions always take time. And reactions to unexpected new events take longer. Look at 9/11, passengers on the fourth flight reacted to the new threat. But it still took them time to figure that out. And they had the knowledge of the earlier attacks to help them make that change. The half hour or ninety minutes it takes for people to adjust is a lot of time for a determined man to kill a lot of people.
But they knew they had a big enough story to dispatch the helicopter in the first place and, to be big enough, they must have had information from the young people tweeting from the site about a gun man.
If they had that much info, which they would have had to have to dispatch coverage in the first place, what did they do other than simply time to cover a story of a mass murder.
Maybe that is their only job. I suppose that is one argument. But to say they didn't know a mass murder was going on is unlikely or they wouldn't have sent the helicopter in the first place.