By placing this comment in parentheses, however, he turns it into a kind of smarmy, backhanded comment that is amusing but also disturbing. He uses this technique four times in this brief essay, each time achieving the same kind of sarcastic, obsequious effect.
King's essay succeeds primarily because horror films themselves succeed. Whether the reader is a fan of the genre (I am not), the fact of the genre's popularity is a strong argument for its ability to touch some impulse common to many people. King likens the appeal to that of riding rollercoasters. Not everyone likes riding them, but they have enough fans to indicate that thrill-seeking, facing fear in a very public way, and paying for the experience as a form of entertainment are all very familiar experiences.
Horror had always been a popular genre, even before the invention of motion pictures allowed large numbers of people to share a group scare. King's breezy essay offers some plausible arguments about why this is so.