First point, studies have shown men are more likely to choose a nice butt with no boobs to big boobs and no ass.
Second, they can improve the shape of the breast and both augmentation and reduction surgeries involve reshaping the breast (beyond making it bigger and smaller)
Third, can we please avoid "womens with big boobs are stoopid!!". It's not true and offensive.
Finally, it does not suprise me that a lot of women find body image to be so importent to them to trade IQ for boobage, although, I would highly doubt the majority of the ones who voted yes to have all that much IQ to trade.