Why does ableism cause harm?
Disability Science Review
1082

I realized another reason why ableism is harmful while discussing with someone why an offhand comment at a lab meeting left me fuming and depressed several hours later.

The problem isn’t that neurotypical people fail to take a disabled person’s perspective. After all, they have the odds stacked against them. It’s hard enough to understand a mind very different from your own, and most people make mistakes. (Ickes’ empathic accuracy studies found that even close couples were surprisingly inaccurate). Furthermore, because most people are neurotypical, most rarely encounter minds so different from their own.

The problem is when neurotypical people fail to recognize that a disabled person has a perspective to take.

Your frustration and indignation as an observer will make no sense to the culprit or anyone else present, because the neurotypical person hasn’t performed any obviously harmful action, and rarely has any feeling of malice. Instead, they make assumptions and fail to ask questions that they never would for any other person. They might assume, for example, that a child who cannot speak cannot understand what others say about them (or may fail to wonder whether they can). Or they might assume that echolalia — speaking in full quotations instead of in one’s own words — has no meaning even for the person speaking…or simply never ask themselves what it might mean.

Consider the difference between these sorts of assumptions and the way the typical American would think about, say, a Chinese classmate or co-worker. An American might not accurately understand his foreign colleagues’ perspective. Depending on his values and laziness, he might not even try to understand. However, he would realize that this colleague comes from a different culture and has a different perspective, and at least in theory, would acknowledge the value of trying to understand it. At the very least, he would acknowledge his colleague had a perspective, even if he considered it wrong.

To fail to recognize that a disabled person has a perspective is cruel and dehumanizing, but not because it involves any ill-intent. Rather, it’s because one is not making the same assumptions about the disabled person that one would make about any other human being. In short, one is failing to treat the disabled person as a person.