The claim is that PP's economy of words meant that the presentations to each level of management got more and more dismissive of the danger, the higher up the chain they went. Euphemisms got more and more bland, until the top people thought "screw it, we're launching."
Note that I'm not endorsing that theory, since I haven't seen the slide decks that got used. It's disputed here: https://eagereyes.org/criticism/tufte-and-the-truth-about-th...
I find that dismissal to be completely missing the point. Tufte wasn't arguing physics, he was arguing that PP euphemisms caused top execs to minimize the danger.