Also, they are talking about a wing. An airfoil is a wing section not the actual wing.
Camber, chord, edges, angle of attack .. these are all described by the airfoil and are key to flight control, including stall handling. How an airfoil gets itself out of the stall state is of great interest to designers.
Airfoils which utilize the Magnus effect (as in this case) do have different stall characteristics. Its not incorrect to refer to the airfoil in that context.. a bit like calling a soccer ball not just a sphere but also a wing, too, which in fact it is to most airfoil designers .. ;)