Because if people only swam where there weren't feeding sharks, there would be far fewer vacation destinations.
Do you think that the increase in shark attacks is due to a decline in the natural prey that sharks tend to feed on? Really? I don't. Sharks don't
attack people as "food", generally it's territorial, defensive, or exploratory. I think it has to do with the number of idiot tourists increasing
and has nothing to do with any other ecological change.