To Centaurus' point:
So many blatantly faulty techniques taught at flying schools and that hasn't change for decades. It all starts from the CFI with lack of supervision of his flying instructor staff.
During my PPL training in the early 90s I studied the theory at TAFE. It was repeatedly drummed in to us (by a number of ex-airline and military pilots) to pick up a wing with the rudder at the point of the stall.
As far as practical application of this, I have never been taught anything else by any instructor (various schools but always at YSBK) in every company type check or flight review to do otherwise. There has always been a strong reminder to never use the ailerons near a stall either. This is mainly in high wing Cessna and Piper Cherokee variants.
I never touched the mixture control during my training until well in to my first cross country (at the instructor's direction). And I was never allowed to use anything more than 2,300 rpm in cruise, irrespective of altitude. I did most cross countries in Piper Archers and thought they all cruised at around 90 knots!
I did question some of this "wisdom" but the general response was, "our airplane, our rules", particularly if you want to pass the test.
It wasn't until I had completed my PPL and was let loose alone that I started to learn this "wisdom" was lacking. And it took a while for me to feel comfortable flying airplanes to the book figures rather than what I had been taught.
Even now I'm astounded by how this was almost absolutely consistent across every instructor I flew with.
Don't get me started about the "avoid anything other than kilometres of bitumen at all costs" rules either!