I try to add ALT to every image I post. It slows me down. Writing a good description takes time, often more time than the post alongside. I don’t think many people don’t take the time to write it because they hate visually impaired users. They are short of time more often than not wanting to be inclusive. A sort of engagement punishment filter will not fix that. And I wonder if the blind community would want to be excluded from all posts without ALT because it would also rob them of the opportunity to learn about the content from the context of the replies. Or the chance to have it described to them by somebody in their vicinity.

The problem isn’t just adding a description to a picture; it’s also the quality of that description. I fear adding a filter like that will lead to more bad ALTs (dummy texts, AI crap, copy and paste of the post, etc.).

My guess is the militant no ALT, no engagement folks are all well enough sighted. Their energy would be better used to add descriptions to the discourse rather than calling out the users who forgot or didn’t have time (and sure, it would include the small group of trolling assholes who don’t do it on purpose). Add a hashtag #ALT and a good description into the replies. Code the client to look for replies with that hashtag when ALT is missing.

So I think the reverse filter will be more beneficial. Filter all posts without ALT so people can add the missing descriptions.