There are serious problems with the linked article.
It appears that the slide pictured in this post (incl. typos) is an inaccurate (fake) copy of what was actually presented in 2003. Either the author or someone else seems to have fabricated it for some reason, perhaps to sweeten the circumstances to better support the author's original contributions to this topic. (Quoted; see below.) Or maybe not, but it's beside the point—which is that the slide as pictured is not an accurate facsimile of the original, but is misleadingly presented as if it might be lifted straight from the source material.
The choice to use this fabricated material for this article and the false claims in it—claims not actually confirmed by the sources that it cites—amounts to what would be considered serious misconduct elsewhere.
Here's the original contribution from the author of this post:
Imagine if the engineers had put up a slide with just: “foam strike more than 600 times bigger than test data.” Maybe NASA would have listened. Maybe they wouldn’t have attempted re-entry. Next time you’re asked to give a talk remember Columbia. Don’t just jump to your laptop and write out slides of text. Think about your message. Don’t let that message be lost amongst text.
This is the main conclusion of the post, and it's a recapitulation of some earlier statements:
Thirdly, there is a huge amount of text, more than 100 words[...] the single most important fact, that the foam strike had occurred at forces massively out of test conditions, is hidden at the very bottom. Twelve little words which the audience would have had to wade through more than 100 to get to. If they even managed to keep reading to that point.
These statements are misleadingly presented in the article as if is they are representative of Tufte's findings. Trying to confirm this reveals that it is not. Worse, unfortunately, is that it can be disconfirmed; the position laid out in the sources cited runs counter to what is purported here to be be a summary of those sources' findings.
The author of this piece would have us believe that Tufte and the investigation board wants us to create better, terser slideshows for these high-risk/high-impact situations—a position that could be described as lean in even more: PowerPoint harder. That cannot be further from the truth.
The position Tufte lays out is that the choice to rely on a series of slides these circumstances represents a serious cognitive lapse. The report of the investigation board itself is critical of the organizational culture where misuse of PowerPoint is "endemic". (Bizarrely, the article actually uses this salient quote—and proceeds to bulldoze past it to present its counterconclusion.) Tufte's notes quote a followup report by a subsequent group that had harsh things to say about an organization that continues in a manner where "instead of concise engineering reports, decisions and their associated rationale are often contained solely within Microsoft PowerPoint charts or emails." The cited sources go on this fashion at length. What they don't do is support the claims or original advice presented in Thomas's "Death by PowerPoint: the slide that killed seven people" article that prescribes the opposite.