The Skeptical Inquirer likes articles like this. This is so well done it deserves hard-copy treatment, you should submit it. In anticipation, here's a little feedback.
Last sentence of para 4: The best tack to take is to attack Johnson while portraying his audience as victims - I don't think you don't want to critisize Johnson's audience in the last sentence of this para. There are several other places where you're also negative about Johnson's audience. I thinkk you should attack only one villain at a time. Johnson appears all the worse if his audience is portrayed as unsuspecting dupes of his machinations. You don't have to praise them, just don't villainize them. Save it for another editorial.
--Percy