The "they" is Chrysler. And what does the cross section of the movable wing look like? I know its thicker in the front. so. based on that i would still consider it a wing instead of a spoiler. The purpose of the movable wing is to create downforce, and not spoil the air pressure like a spoiler does. There is a gap under the movable wing so the air flows under it just like your diagram. It might not be a perfect aerofoil design, but it is a wing and not a spoiler. If it were a spoiler, it wouldn't need a gap under it, and it would look how the picture of a spoiler looks. The gap is let the air flow under it and create a low pressure.