I wouldn't deny them, no, however, when you are placed under arrest, not only are the cops responsible for your safety, but they are also responsible for your property, so if they leave your car on the side of the road, and someone breaks into it while you are on your way to the police station in the cruiser, they are responsible for that too. That's the difference.
I'm not saying all that didn't go out the window here, but that's the difference.
You are right. They know now they should have rendered first aid, but at the time, if they didn't think his life was in danger would they have known then? That's why they are on trial.