Do airliner spoilers really "spoil" lift?
You modified the lift distribution diagram by adding spoilers without showing how that modifies the lift of the wing. The trailing edge of a wing controls how much lift is produced, whether you call it flow turning, circulation, or whatever. 

Your diagram implies that lift is produced regardless trailing edge position. If this were true ailerons would have no effect since they only occupy the trailing quarter of the typical wing. Look at the camber line of the wing in your diagram with and without spoilers and you'll see. Flow does not turn with spoilers deployed, so you lose lift and gain a lot of drag.



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  Extending the wing flaps increases the camber or curvature of the wing, raising the maximum lift coefficient or the upper limit to the lift a wing can generate. 


A spoiler of the variety shown in the first diagram works like a split flap upside down, reducing camber and maximum lift coefficient.


inverted

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