"the way of life, especially the general customs and beliefs, of a particular group of people at a particular time" <end quote>
-one of the definitions from Cambridge Dictionary Online
the way I learned in sociology was that it also includes language.
ASL reflects the attitudes and ways of doing things of Deaf culture.
-from World Federation of the Deaf: "Deaf people as a LINGUISTIC <bold highlight mine> minority have a common experience of life, and this manifests itself in Deaf culture. This includes beliefs, attitudes, history, norms, values, literary traditions, and art shared by Deaf people." <end quote>
hoh do not have a culture in the same sense because there is no shared history, belief system, art forms, language, values and so on
I think part of why this is so hard for you to understand is because you haven't learned ASL, don't know what it means to look at things from another lens...