Yeah preventing visually impaired people from using Tor Browser seems like a bad choice. As cypherpunks suggested, better to file a UX bug with Mozilla so they can work out how to do this properly.
Trac: Status: new to closed Resolution: N/Ato not a bug
So assuming we disable accessibility services by default, how will our visually impaired users use Tor Browser?
Ah, when opening #33445 (moved) I was thinking that those users could just enable it if they need it, but yes, maybe they can't access easily the preferences when accessibility services is not enabled.