HalcyonDaze
Contributor
The difference is (at least some) humans understand spoken word. Critter acting out of instinct -- can develop an instinct that says you eat this type of food, your entire species go extinct. We do this to wildlife preying on livestock, tigers preying on humans, what makes sharks so special.
Pretty much all of the examples you quoted are examples of humans deciding they want the environment "sanitized." I've never seen someone pull up a credible account of the "rogue shark" hypothesis which held up under scrutiny. It's quite simple: environment with big predators + humans, pets, or livestock = occasional predation. No need to conjure up the animal version of Jack the Ripper; frankly I feel safer in the water than I do around humans (okay, I live in Miami so that's not putting the bar very high).
The only way predator culls work is by crashing the predator populations, which in the case of the ocean is metaphorically dumping chlorine in there to spare us any unpleasantness. While I agree that in this case it seems like the sharks had gotten into a supposedly protected swimming area, I'm not completely surprised; big sharks can get into some pretty skinny water. Years ago there was a rather famous case where a full-size great white got stuck in a tidal pond in Massachusetts and a lot of effort was required to point it towards the exit. I've come across an ~8-ft tiger in 3-4 ft of water on a grass flat.