It's likely following HTDP:

https://htdp.org/

It could be following PLAI:

https://plai.org/

But that's not normally run as an introductory course, which is what OP mentioned Racket being used for.

Might have been Waterloo's Introduction to Functional Programming (CS 135). I have TA'd (technically ISA'd) that course several times and helped countless students in office hours. The struggling students didn't just hate Racket, they hated the whole HTDP philosophy of following a "design recipe" and writing documentation prior to implementing a function. Most of those struggling students essentially waited till the last minute to do the documentation, completely flouting the intention of the course.

I don't know if the strong students had the intended approach since they were never in office hours asking for help!

I loved that course so much. I remember some seemed to hate it because "when are we ever going to use Scheme in real life?"

I really loved the course too. That's why I kept working for it! It always made me sad when students hated the course, which was most of the ones I met in office hours. I think the students who really loved the course did well enough that they didn't come to office hours, so I never met them!

Waterloo’s CS135! I’m in it right now.