I agree with you. I think there is a difference between swimming & chasing. This didn't look like chasing to me. It looked like a diver doing a regular dive happening upon a school of fish & then slowly swimming with them. To be fair, it also looked like the diver was touching the bottom which I personally don't agree with.
I agree that showing everyone the beauty of the underwater world can convince people it's critical to protect it, but I have seem so many amateur photographers/videographers touching & damaging the reef that it makes me ill. And to know that the experts do the same is just disgusting! I understand that it's even harder to draw the line when it's your livelihood at stake, but crap like this shouldn't happen.