RMS didn't say that. He only said that GNU shouldn't endorse or assist the use of nonfree software, even for blind users.
He might say what you suggest, or he might have better thought out position, such as acknowledging that society's lack of provisions for people with disabilities is also a social problem, or the way copyright law blocks blind users from helping themselves is a social problem, and using nonfree software might be bad but it could be the lesser of two bad things. I don't know.
And if he said that GNU should endorse nonfree screenreader software, would the moaners be silent?
When GNU was doing nothing, no one complained. When they start a push to help blind users, they get moaned at for not endorsing nonfree software (as if that should suprise anyone!). Some people just like complaining about other people's work.