You have to give people the opportunity to prove themselves. It is complicated for deaf actors. There are deaf actors who don't speak or speak very little. They can never compete for roles where speech is required where Marlee can. Most profoundly deaf people have speech that is very difficult to understand.
Access is a problem all around women, seniors, and minorities.
For example the box office value of a woman once she gets past forty and a man past fifty really starts declining. This kind of discriminatory behavior is unfortunately occurring all over the place. The deaf community is in a favorable position because they have a national theatre and training groups of their own to get them started. Deaf actors have often acquired very valuable skills and experience before they get their break. On the other hand, I empathize with the blind community.