The real issue though is the accuracy.
It cannot work properly because the image can't be described without the context (both local context, e.g. the post the image is contained in and larger context, like the author, culture of the author, etc.).
Now people often suck at writing alt text as well, but at least they don't deliberately do it wrong.
https://bsky.app/profile/karidru.bsky.social/post/3ktvvtvjtzk2u