Several universities still teach racket as an intro language. Ex: Brown, Northeastern, Northwestern, etc.
The authors of Racket specially avoid arguments about teaching language X in introductory CS. The pedagogy and curriculum are significantly more factors in effectively teaching CS [1]. The design of Racket with its restricted languages reflects that.
The speaker in the talk linked is a previous Ph.D. student of the author above.
Northeastern, Brown, Northwestern, and Waterloo all use the approach in HTDP as far as I'm aware, even if they don't use the book itself. Racket just happens to be the language of choice (or rather X Student Languages are, not even Racket) because they fit the pedagogy well.
The authors of Racket specially avoid arguments about teaching language X in introductory CS. The pedagogy and curriculum are significantly more factors in effectively teaching CS [1]. The design of Racket with its restricted languages reflects that.
[1] https://www.janestreet.com/tech-talks/curriculum-design/