I would disagree that there is no "load" on the airfoil. Wouldn't load be a resistance against a force whether something is held in place or whether it is dead weight plus Nz?
Think about that.
Hold a wing section in place. Now consider a 'scale weight' for your section. Your assumption of simply holding it in place, accounts for the weight of the aircraft, and the weight/thrust has no bearing on the airflow characteristics?
Would you assume that the same aircraft. lightly loaded, would produce the same reactive results moving through the air, as the very same aircraft at max weight?
It IS the same wing section after all....
Look at stages of flight, at the beginning, when the ac is loaded with fuel, the angle of attack is much different than the angle of attack when the aircraft is near destination with much less of a fuel load.
Using the principles that you are stating, the wing section would simply have a fixed angle, and require more thrust at the heavier weight, not a different angle of attack?