Here's why:
* Deaf Culture: The Deaf community is a vibrant culture with its own language (ASL), traditions, and values. Using a capital "D" acknowledges this culture and the shared identity of Deaf individuals.
* Distinction: Capitalizing "Deaf" distinguishes it from the medical term "deaf," which refers to a hearing loss without the cultural connotations.
* Identity: For many Deaf individuals, being Deaf is a fundamental part of their identity, not a disability. The capital "D" reflects this sense of pride and self-identification.
Using "deaf" (lowercase) is generally acceptable when:
* Referring to the condition of hearing loss in a medical context.
* Describing someone who has a hearing loss but doesn't identify with the Deaf community.
In summary: While "politically correct" is sometimes used to describe these usages, it's more accurate to say it's respectful and considerate to use the capital "D" when referring to the Deaf community and their culture. It reflects the shared experience and identity of Deaf people and their sense of belonging.