- to "retweet" without notifying the person and being linked to as a "quote tweet" on the OP
- to share a post in a controversial context where many people are blocked by the tweeter in question (if you're blocked by someone, you can't read their tweets)
- to share a post you expect will be deleted shortly
- to screengrab a couple of posts that make up necessary context and wouldn't make sense if retweeted on their own
To your point about people using screenreaders etc, it seems to me that it would be fairly trivial (cputime aside) to OCR tweets and automatically apply alt-text, but instead they rely on the uploader to enter it manually.
There are definitely accessibility issues with using images as a text medium, mainly that the poster has to be aware of the accessibility issues and specifically choose to alleviate them. But that was done here.
We are at the stage where business critical market moving press releases are now made on twitter as an image by twitter’s ceo because twitter won’t support longer text, two days after twitter deployed an major update to alt text [1] .
[1] https://techcrunch.com/2022/04/07/twitter-alt-text-badge-ima...
It‘s not a slur (yet)
No offence was intended though (;