I am not sure if I understand this correctly. You need to be able to touch someone to understand them or that they shouldn't use sign language that depends on mostly visual context to understand? Can you explain me what you find offensive? I want to understand this so I can avoid offending someone.
Sorry if this sound stupid. I'm usually not around many deaf-blind people, and I had one as classmate in college once. I learned a lot from her, and I even made sure that I close my jacket at her request, so that she can see me better.
