[throwawaysocks]

It's really useful to distinguish technical fields from engineering and especially natural sciences fields once you get past K12. STEM is not actually a very coherent grouping.

Almost all CS programs are relatively flat, but many science programs have longer chains of linear or parallel pre-reqs.

Math programs differ from both because long chains of pre-reqs in Math often correspond to required maturation rather than required knowledge (e.g. the Calc sequence as a pre-req for algebra courses).

[thaumasiotes]

Math and CS professors and students complained loudly about the lack of prerequisites. It did great harm to the curriculum. Defending it on the grounds that math and CS don't need long prerequisite chains in the way that other fields do misses the point.

[throwawaysocks]

WRT CS, my comment was meant to be descriptive, not prescriptive. FWIW I agree with you, but what I said is largely true of CS curriculum in the US.

I'm not sure whether I agree with you regarding math. I think pre-requisites should reflect required knowledge accurately, and should leave required maturation to the student and his/her instructor. Requiring the calculus sequence prior to courses that contain no calculus strikes me as a silly historical accident, for example.

[thaumasiotes]

> Requiring the calculus sequence prior to courses that contain no calculus strikes me as a silly historical accident, for example.

Sure, but I haven't said anything about that.