What I suspect CONF iture misses is that while the calculation of AoA is not directly affected by thrust and/or airspeed, airspeed (and Mach at high speed) *does* figure in the Coefficient of Lift calculation from which AoA is determined (said calculation is what I'm guessing he means by "performance"). The presence of the graph was simply to show that a correlation exists - not the correlation of a specific type of aircraft.
Well I wouldn't be so sure of that - such a relationship is fundamental airmanship I think.
But anyway, I think you have it a bit wrong - one doesn't calculate AoA from CL but CL from AoA. CL doesn't figure directly in assessment of whether the aircraft is near stall or not - that is a simple function of AoA and Mach Number. If AoA is measured (as it is) then at low Mach that is enough to determine stall margin. When at higher Mach the boundary needs to be adjusted (which is why a simple AoA gauge cannot function as a stall warning when airspeed information is lost), but even then it would be possible to work with a default value which, even if it did not prevent "stall", would serve to avoid the sort of shambles that we see in AF447.
Fair enough, but if the pitch attitude cannot be reduced for whatever reason and the aircraft approaches a low-energy state (precipitating approach to stall), the only way to maintain a sufficient Coefficient of Lift and therefore AoA to keep the aircraft flying is to increase speed, which is done with thrust.
Assuming that is, there is enough thrust to maintain level flight and have something left over - which is not always the case.