Thanks for posting the link Chesty.
AOA of the aircraft is the same as it was before you extended the flaps because your resultant velocity vector/flight path vector hasn't changed nor has your pitch. AOA of your wing may have changed along the area of the wing where the flaps are extended.
(I say may have as flaps are also used to increase surface area/aspect ratio of the wing, thereby creating more lift without having to increase wing root AOA. Fowler flap/slats are a good example)
Lets get back to basics of the original post Chesty.
AOA for an aircraft is defined as the angle between it's Pitch and it's flight path vector.
Do you disagree with the above definition or do you think no such definition exists or is "stupid"?