Good question DAR, remember we are talking of a wing that is already stalled. It has reached its burble point and the airlow is in a seperated state over the top of the wing , no laminar flow at all. Any increase in the ailerons deflection is only increasing drag and, of course, increasing yaw.
Yaw + stall = spin. You cannot autorotate without yaw. Fat high lift wings with washout, that you find on most GA planes, are tollerant of sloppy handling to a point. Most will even recover from a spin by relaxing the controls if they were originaly trimmed for level flight and it is only in the insipient phase. Try putting a Mooney in a deep stall and use aileron to level the wing without rudder. You will see what I mean.
I think that POH's don't bother to tell you NOT to level your wings in a stall with ailerons for the same reason they dont' tell you NOT to push the stick forward to climb. It is something that you should have caught onto a long time ago.
Helicopters put an end to the developement of fixed wing STOL in GA aircraft, and there were certified AC with flaperons.