https://www.nad.org/resources/american-sign-language/communi...
Additionally in America up until recently the Deaf community was oppressed, told there was something wrong with them, and forced to use a communication system that doesn’t work as well for them. This led to lower education outcomes, depression, and other ills. This led to a strong Deaf culture and identity, so as to not allow the hearing to tell the Deaf that they are somehow damaged or not complete.
The capitalized word is meant to highlight the cultural and social parts of living in a community with other Deaf people. You also would not write American in the lower case.
Being "deaf" is about the handicap, about the loss of hearing and other problems.
Being "Deaf" is about being a member of a community, about the keen visual sense, about communicating in a Signed Language, and so on.
Why not capitalize every Noun like in German
Did you see my careful use of the capital letter?
+it’s almost 100 degrees here
One example: my wife and I realized that we are a lot more able to read the mood of our children by just looking at them than hearing parents. We just "see through" our children.
Even in hearing people, I'm reminded of those who are not just big readers but are used to reading; those who can skim and still obtain 100% of the writer's meaning as opposed to others who aren't so comfortable, fluent, or quick readers — but are not uneducated, just not accustomed to the medium.
Of course the bookworms then have an easier access to education in written form (and that's why I am both a Dipl. Ing. FH in IT and a Bachelor of Law).