This thread pertains to recreational divers primarily diving in Florida and the Caribbean, and their most likely shark encounters (if any) will be with gentle Nurse Sharks and minding-their-own business Caribbean Reef Sharks.
To be fair, the thread was started as a general "fear of being eaten by sharks" discussion. There was no specific region or species of shark specified. It's a disservice to the discussion to claim that shark attacks never happen. It's more useful to determine how rarely they occur and under what circumstances.