Basically because it was correct! Your comment
The angle of attack at which a modern commercial jet stalls at 0.8M is something around half of the angle of attack at which it stalls at Vs1g.
is totally confusing.
Firstly 0.8M has nothing really to do with 'airspeed'
Secondly you are mixing a Mach effect at an
unstated 'g' with a stall at '1g' at an
unstated airspeed! Absolute confusion. It will still stall at 'Vs1G' at high level, will it not? Just a different Vs due to airflow Mach effects.
It has everything to do with angle of attack.
- is correct. Whatever the angle of attack at which an aerofoil will stall (
yes, at whatever Mach number), 'airspeed' is irrelevant. I can stall the same high performance jet at sea level at 140kts straight and level 1g or 400kts in a manouevre.
However, all of this is pretty much irrelevant to the thread.