The frilled shark isn't the biggest of sharks. It has a clean record where maneating is concerned. So why are its rare appearances greeted with such freaked-out responses from humans?
Basically, the 2m frilled shark, like the goblin shark (which looks nothing like it, but engenders similar responses and may by 5m long, to boot) don't fit our picture of what a shark looks like. The frilled shark instead fits our picture (inaccurate though it may be) of what a prehistoric monster looks like. With a gill "frill" extending around the body, an elongated shape, and a relatively blunt head with 300 teeth, it doesn't look like a medium-sized, harmless animal, even though it is one. It simply looks weird, and we go crazy over it (hint to SyFy Channel: an 8m frilled shark would make a great centerpiece for a horror movie.)
Oddly, the head and even the teeth of the frilled shark bear an interesting resemblance to those of the leopard seal. This fierce Antarctic predator (with at least one definite human death to its credit) can be 3m long and has no business looking like a shark. But that's convergent evolution for you.