Employment discrimination is against the law in various circumstances, which is something for both employees and employers to know. For instance, employers aren't allowed to turn down a potential employee just because he or she has a disability. As long as an individual is capable of performing the job, he or she should receive a fair chance at employment.
If someone develops a disability after being on the job, he or she should not face retaliation or be fired simply because of the disability. There are cases when an individual can't continue at a job because he or she can't do the work, and that's a fair reason to have the individual leave. However, simply letting an employee go because he or she is handicapped is against the law.
Employers do have to make reasonable accommodations for employees with disabilities. For example, if an older employee has trouble standing for many hours but can otherwise complete the job, the employer may want to provide a chair or adequate breaks to allow the individual time to recover during his or her shift. If an employer is not willing to provide reasonable accommodations without a good reason, then the disabled individual may have a right to a claim.
Disabilities change people's abilities, but that doesn't mean they are inept. Those with disabilities deserve a fair chance at a job in the traditional workforce. So long as an individual can perform the work, there is no reason to discriminate against him or her due to the disability or his or her appearance due to the disability.
Source: ADA.gov, "Subpart C—Employment," accessed Dec. 28, 2017