Because, sadly, a lot of instructors only teach what they were taught themselves, and with quite a few low time pilots becoming instructors, the quality of flying training slowly degrades with each new instructor.
if your instructor cant balance an aircraft, or doenst understand the significance of balanced flight at low speeds or in turns, then find another instructor. sadly, a lot of pilots think that getting along well with their instructor means they are a good flying instructor, sadly, it quite often not the case, i was fortunate to have an ex RAAF pilot as my initial instructor, and later instructors have been ex military as well, and some flights were a disaster, he had some students in tears, and never sugar coated anything, if you stuffed something up, he told you so, and you didnt ever stuff it up again. and i have flown with other students that came from other schools, telling me how great their instructor was, yet still had no idea about the basic things like stall AOA, and not using rudder as shown in the video above.