> I guess a lot of folks consider games exclusively for folks without those accessibility needs, so maybe that's why something like Dear ImGui can live for years in thousands of projects without anyone complaining about accessibility. But, I wouldn't consider it for anything that isn't specifically about graphics and I don't think anyone else should either. (No one has to listen to me, but I think less of them.)

Immediate mode UIs are mostly for debug menus, not even gameplay/graphics. It doesn't need to be accessible to anyone except for the developer(s) choosing the library and making the game. (If the developer has different needs, obviously they can choose another library, unlike users who must live with the developer's choice.) The fourth sentence in the linked ImGUI repository explains this intention very clearly.

You can spend all this energy imagining malice and thinking less of others, but doing so does not add merit to your critique. Nor does it advance the cause of software accessibility.