I haven't seen the associated talk, but (a) I would imagine the author chuckled while reading this, because it's sort of a joke among scholars, and (b) the point is likely focused much more on the context of presenting research (e.g., at conferences) rather than a blanket ironclad rule for all presentations you ever make ever.

While I think there's some validity to your point that the author's presentation suffers excess verbosity, I'm not too worried about it because the linked slides seem more meant to act as a reference document than an example of a good presentation, and the level of text is just fine for that purpose.

There are presentations that you actually present to an audience, to which this point is valid.

But lots of presentations, including this one I think, are merely used as a means of conveying information (yeah, not my favorite way of doing so, but being a contrarian doesn't do anybody's career any good), and those are indeed intended to be read and need to have explicitly all the information that you otherwise would be speaking and addressing.

I always thought this was funny. We were taught this in grad school, but hardly anybody followed this guideline. "If there's too much text on the slide, the audience will be busy reading the slide, and not paying attention to you". I try to have just the main point on the slide, then I can talk around it. The details should be in the slide notes, if you need reminders.

My guess is probably there is a difference between slides used for presentation and slides used for reading myself alone