The text in the first paragraph does not assume that ASL inhibits English. I think they did a good try to explain the need for interpreters. Before I became HOH I just assumed that all deaf were fluent in written language. I think many hearing believe that. When encountering poor written language they assume there must be something wrong with the person.
Here in Sweden younger deaf persons usually do read and write well. The goal is that deaf kids should be bilingual. Historically this has not been the case. Deaf children learnt sign language from friends, but since sign language was not used in education, they could not really learn much about written language or other subjects. When not knowing the history it is a surprise when captioning and writing is not enough. Of course even deaf with good written language skills should have access to sign language interpreting if wanted and if sign language is their primary language. That part is maybe missing from the text, but in general I think it is neccessary to inform hearing about that not all deaf communicate alike.
