This his reply to instructions telling him he can ask for sign language or use text relay if he cannot use his voice. I hardly see this as discrimination. This is in no way different from a perfectly able person saying it's discrimination to expect me to read and write! Sign language is the language of the voiceless.
Life isn't perfect. Of course we should do as much as we can to make life for the disabled easier. But seriously people feel so entitled and expect so much from everyone. People need to accept that not everyone can accommodate 100% of needs. Governments should, but not private entities.