This is the business world people XD No matter how unfair it sounds, it's kinda true that, because of all the media attention Ayu's deafness got, if random people (fans or not) see her in a CM, they'll think about that issue, and not really about the product. Just like, with Koda, they'll think of the rotten fluids and stuff.
The poll doesn't mean she will never have CMs again
Just that, right now, companies are cautious when considering her. And I guess the price would be too high for most anyway.