The above mentioned company is an example of one of those organizations who practice informal discrimination and the basis for discrimination is not openly communicated but are known to most managers. In this case, the organization's stance is ethically unjustifiable. An ethical organization should hire individuals on the basis of their qualifications, capability and job suitability. So if a disabled individual is unable to perform the job he or she has applied for, their application may not be accepted, but if they are capable of performing the work, the organization should not reject them just because they have some disability.

Yes as a staffing manager you do have ethical and social responsibility to change the stance. You should demonstrate some examples of disabled persons attempting the impossible if they have the zeal to perform. Many disabled persons have achieved a lot of big things in their life. Some examples are Albert Einstein, Alexander Graham Bell, Stephen Hawking, Thomas Edison, Helen Keller, Beethoven etc. You should convince them that disability does not necessarily stop a person from performing any activity as long as they have enough motivation and a little bit of support. Also since this hiring policy is also illegal, you should provide senior managers with information regarding the legal consequences of this informal policy. If they still remain unconvinced you should refuse to comply with an unjust and unethical policy.