@HarryMann:
it probably comes from very high aspect ratio sailplanes, as well as some military aircraft (built like brick ****houses)
As well as from vintage taildraggers, like Cubs and Champs, which didn't feature things like differential ailerons -- they probably hadn't been invented when these aircraft were designed -- and with which margins for error are greater.
@Eutychus:
I thought the critical factor was not pitch (which I understand as the lengthwise inclination of the aircraft relative to the horizontal plane) but angle of attack (which I understand as, roughly speaking, the angle of the wing to the airflow).
Your understanding is basically correct. The Wikipedia article is imprecise.
Most of the time (e.g., calm air and unaccelerated (1G) flight), the airplane's pitch attitude and its wing's AoA are coincident -- tied to each other. (Which is not to say the airplane's pitch attitude and AoA are the same.) It gets more interesting when gusts with vertical components, G-loading and other factors are considered.
It's rather common for the wing's critical (stalling) AoA to be exceeded even though the airplane's pitch attitude is not as high.