Some background: LaHaye and Jenkins are both premillennial dispensationalists, who believe that a particular scheme of Biblical history and prophecy, as outlined in the Scofield Reference Bible, with further refinements made by Hal Lindsey in the 1970s, gives a surefire preview of the End of the World. The Left Behind series is basically a novelization of the Scofield-Lindsey scheme of the End Time.
Clark does not share LaHaye and Jenkins' belief in the truth of the Scofield-Lindsey scheme. He puts it like this:
Let's be clear: there is nothing literal about this convoluted, herky-jerky, cut-and-paste collage. Their reading is neither literal nor linear -- arbitrarily leaping about from Revelation to Ezekiel to Zechariah to John Birch, leaving no context intact.
Premillennial dispensationalism is as far from a "literal" reading as you can get. These folks are not orthodox Christians and they're not illiteralist "fundamentalists" either. So don't buy their pose.
Clark regards the Left Behind series as heretical, dangerous, and fundamentally un-Christian.
UPDATE: Combine end times genre fiction with the closely related field of Young Earth Creationism and you get . . . the velocirapture!