The essay you linked is titled "The Cognitive Style of PowerPoint: Pitching Out Corrupts Within". The link from that page is to an excerpt of an essay titled "P

The essay you linked is titled "The Cognitive Style of PowerPoint: Pitching Out Corrupts Within". The link from that page is to an excerpt of an essay titled "PowerPoint Does Rocket Science: Assessing the Quality and Credibility of Technical Reports". Given that they have different titles, I suspect they are not the same essay, and the latter essay concludes not with PowerPoint being unable to transmit information, but with a (sensible) recommendation to use technical reports when technical reports are called for.