As I see it, @aral has been calling out ableist behaviors, not arbitrarily labeling people, and most certainly not @matt (prove me wrong).
The worst part of ableism in software development is to treat accessibility as yet another "requirement" in the list that consistently gets ranked down, kind of a bonus of grace. Like with pushing out Wayland fully knowing that this will exclude people.
It seems to be hard to imagine for some what this means for people depending on features like e.g. a screen reader that is fully functional, and works during installation already. And sometimes this ignorance shows in very disappointing statements and replies.