Answer:
Mairs responded by telling them that their depiction was painful to the disabled people, especially when it comes to their self-esteem. This makes the disabled people hopeless in conforming to the society that they belong–thinking that they'll never be good enough when compared to the able-bodied in the advertisements. This makes them invisible to the society.
Explanation:
The local advertiser she asked responded to her that they didn't include disabled people in their advertisements because people might get a wrong notion that the advertisement was only for the disabled people.
For Mairs, it is important that the able-bodied people should also recognize the disabled people as an important part of the society.