Agreed, thanks for saying this. I'm always a bit weirded out when someone tries to tell me I'm not disabled because I'm successful, so of course I'm able. I get that, probably from a pure linguistic perspective, the word "disabled" has negative connotations. In actuality though, there's a rich disability community. Chicago (I think, anyway) has an annual disability pride parade. We live in a culture that tries to strip lots away from us when we're disabled, and sometimes it's all we can do to claw some of that back. So while someone may mean well by claiming that someone who is successful or competent shouldn't be called disabled, it takes away that person's autonomy and ability to self-identify, and also removes success and competence from what people think of when they think "disabled." IOW, if someone can say that the word "disabled" doesn't apply to a person because they do something well, others in the set of disabled people have it a bit worse off because they're both faced with a challenge and not able to handle it well.

That said, I didn't think this was the author's intent. But I can't count how many times someone didn't think I was blind because I wrote well, and they couldn't conceive of how someone who couldn't see could write a coherent sentence. :) Try applying for jobs in that expectational landscape and, well, it's challenging and is why I don't even like working for others anymore.