The last video posted above indicates to me that the pilot was likely the unfortunate victim of circumstance rather than poor technique. Although the lack of flaps in the final turn does appear to be at odds with recommended practice.
In that video the engines can be heard throttling down prior to the aircraft entering a very conservative left bank (maybe 10 degrees). Towards the middle of the turn, the bank angle is increased to maybe 15 to 20 degrees, and that's when the stall set in and the aircraft could not be recovered.
Hardly looks like a foolhardy manoeuvre to me, more likely a combination of temperatures and a possible wind shear or gust turning a manouevre the pilot had done many times before into an accident.