[Jtsummers]

The critique wasn't that they are innefective, it's that they contain poor pedagogy. Their specific examples are from arithmetic videos, where the presentation and notation is inconsistent or the examples/problems were insufficient and could easily lead to misunderstanding the material. Your experience is with the calculus videos. It's possible the criticism doesn't apply to them. Or because you were a more advanced student of mathematics and were being provided feedback from your course any poor use of notation or poor problem sets wouldn't have had the same, potentially negative, impact on you.