Did they go out hunting the shark, or just shoot at it in defense of the man?
I didn't read the article, just skimmed it, but if it's the latter, I don't feel sorry for the shark at all. Yes, the man was in the shark's habitat, but I'm sorry, if a prey is hunted by a predator, that prey isn't just gonna say "welps, I guess I'll get eated cuz that's nature", no, they are going to try to defend themselves by any means necessary. Animals in nature have means to fight off and yes, harm, predators, so I'm not going to feel sympathy for a shark if some humans, in trying to defend another human, unloaded some gunfire into the shark.
If they went hunting the thing down? If they just took a boat into the ocean and were like "Hey what's up shark, eat this!" *bratatatatatatatata* then yea, there's a valid point there.
But not in self defense. Don't wanna get shot at? Don't eat a human.