Earlier quoted context omitted.
I appreciate his attention to pedagogy. Even small things like noticing that students learn better with Matlab/Octave than with R or Python is the kind of observation that takes a combination of knowledge, effort and caring about teaching.
I could be wrong, but I think it has nothing to do with that, and now to do with the course being so old that R and Python weren't the standard ML languages yet.
I agree with a sibling comment that it was python and R were well established at the time.
Also makes you think about how comprehension is closely tied to expression even for ostensibly similar languages.