It seems to say that "it is not an infringement of copyright for an _authorized entity_ to reproduce..."
“authorized entity” means a nonprofit organization or a governmental agency that has a primary mission to provide specialized services relating to training, education, or adaptive reading or information access needs of blind or other persons with disabilities;
The owners would have plausible deniability I feel, they don't know whether their users are deaf. Then it would be down to the copyright owners to address whether individual users had rights to format-shift audio tracks [they purchased] in to a format they could consume [specific language subtitles].