Why the disabled might get poor medical care (and otherwise fair poorly)

It could be the laws intended to help the disabled that get in the way. e.g. for doctors, in the US, they're required to provide for deaf people communication of the person's choice - writing on paper doesn't work if the person would prefer a sign language interpreter - with no additional compensation from the government or insurance companies for this.

Consider some comments on this in a New York Times article:

The woman later called again to say she would rather have a sign-language interpreter. Fine, Brooks said, and asked his assistant to make the arrangements. As it turned out, an interpreter would cost $120 an hour, with a two-hour minimum, and the expense wasn’t covered by insurance. Brooks didn’t think it made sense for him to pay. That would mean laying out $240 to conduct an exam for which the woman’s insurance company would pay him $58 — a loss of more than $180 even before accounting for taxes and overhead.

So Brooks suggested to the patient that they make do without the interpreter. That’s when she told him that the Americans With Disabilities Act (A.D.A.) allowed a patient to choose the mode of interpretation, at the physician’s expense.

Sounds like a great way to encourage various non-explicit forms of discrimination against the disabled - e.g. being busy when they are looking to book appointments or failing to suggest additional followup visits that might be important in addressing the patient's concerns.

Consider as well the effects on the employment of disabled people following the adoption of the Americans with Disabilities Act. According to a University of Chicago analysis, this resulted in a decrease in employment amongst the disabled as well as a freeze in their wages.

Good intentions don't always lead to good conclusions.