I guess it's also true that the cost of a false negative is unknown and not felt. It would be a really extreme case to be forced to say, "Hey, remember that woman we didn't hire two years ago? She went off and founded Company Y that's now eating our lunch." With a false positive, you feel the pain of cleaning up their messes until after they're gone.
Finally, sad to say, the majority of job applicants are not competent to do serious engineering work. A negative bias is right most of the time.
