Well, I guess “dangerous” is a better word than “hostile.” There are, of course, critters larger than the hammerhead shark, but they tend to be “gentle giants.” The blue whale, for example.
In a similar vein, bees can be dangerous to humans, but I work in my own yard and customers’ yards, and have not been stung once. My guess is the bees go about their business and ignore me; perhaps the sharks near the islands off Ecuador had the same philosophy.
As for two hammerheads bumping, I guess that is a natural consequence of the way their eyes are set–on the ends of long stalks. They must have some difficulty getting really close to anything…