"Here's an AI to write Alt-Text for your images" is exactly what @danmcquillan argues is the "management of austerity" at the core of current "AI" systems: Marginalized (in this case blind) people get a shitty version of the real thing because we can't be bothered ("can't afford") to give the real thing.
Writing alt text is not some annoyance that you should automate half-assedly. Write the fucking description of you post an image. It's just part of what you do when posting a fucking image.