By characterizing disability as a discrete ‘target’ group, the aim is to excuse the creation of products and services which do not cater for disability. “Oh I’m not making things for disabled people. But I’m sure someone else is, don’t worry. Such-and-such law of economics states it must be so.”
Disability does not work that way, though. It isn’t a discrete community or field of interest. It is complex, multifaceted and pervades all kinds of cultural identity through race, socio-economic level, gender identity, and faith. If you create an inaccessible product or service, you are almost guaranteed to be disenfranchising someone, including your future self.