Kept thinking about this some more and came to the conclusion I really disagree with this being either gaslighting or ableism.
You really don't require any more abilities to log on to IRC than you do to use a browser or a mail client. It's something we expect from people nowadays and can be learned in 5 minutes.
What is ableism is excluding people from your community by switching to a platform they can't use. Ask the blind people in this thread what they think of Discord.