Cli-Fi
John J. Falco
It's rare for false killer whales to attack dolphins, so the dolphins probably wouldn't have seen them as a threat. Also, as Attenborough said, it seems these groups knew each other from way back, so while it is a mystery, it's not as if the dolphins used brainpower to turned a dangerous situation around.
My mistake from the way he described it it sure sounded like they were going to go after the dolphins and I'm well aware of the aggressive nature of the killers. My childhood was crushed when I learned how much of a predator they are.
It looked like the dolphins at first were running away from them as if to get the food first