I think the original lamentation was, I don't know, unsurprising in the content. The outlined problem not only affects Maths, but pretty much all other areas of education also.
Reading through the PDF, it seemed that the main point is to remind that there are multiple ways to teach stuff to students, and teacher has to be able to see what is the best way to answer the question by a student. Different people, different methods - should be nothing new to a good teacher.
Besides, I don't consider any of the Maths stuff I got my hands on during High School "unnecessary". All of that **** has found a way to be applied in my work. However, courses held by Department of Mathematics during my stay in University could best be described by that lamentation. Luckily, I realised quite soon (probably second lecture of Linear Algebra) that I didn't have to attend the lectures... and that was an eye-opener of the University world. I could read and learn stuff all by myself.
Later on I cursed the Department of Maths to deepest pits of Hell for allowing to lecture the Linear Algebra course in about the dumbest possible way imaginable and providing worst possible learning material. Writing proofs down from the black board had to be one of the best ways I have yet seen to waste students' time. Even today when programming computers, I find my capabilities severely lacking in Linear Algebra, or in Matrix manipulations. How I wish it would have been possible to attend the Maths courses by the Faculty of Engineering, but no.
Luckily, Physics courses gave a lot more reasonable explanations of those fancy mathematical terms I heard during those torture lectures. And I'm still wondering afterwards how well could I have actually understood all that stuff had the approach been different.