This is great advice for the right context, but can be the wrong advice for different situations.
If the slide deck is meant to be something that can be shared around and make sense without you, it needs to have a lot of text on the slides. Even putting it in the speaker notes doesn’t work.
So make sure you know your audience and the context (also important presentation advice)
Counter examples:
https://web.archive.org/web/20161223041152/https://idlewords...
https://boringtechnology.club/
Those talks don’t have too much text on slides, yet they can still be shared as text by including the speaker’s script aligned with each slide. They also have online video versions for comparison.
Yes, but then your audience doesn't need you to give the talk.
If you need to share the idea of the talk using just the slides then that’s a totally different problem. You shouldn’t make the slides worse for people who can attend the talk.
This is a case for their being two slide decks. Or rather, that slides can be used as a shareable graphic-heavy document OR as an aid to giving a talk, but the same deck can’t be good at both purposes at the same time.