OK, if "toy project" isn't the right word, then perhaps, "unethical" or "exclusionary" would be better words to use.

I judge software harshly that could be useful to folks with accessibility needs that don't try to address it (within bounds of their resources and capabilities, obviously lots of OSS just doesn't have the ability to deliver an accessible experience for tiny little throwaway apps). I definitely choose technologies to use based on whether they can be accessible with a little extra effort on my part. I'm not necessarily good at it, it's a complicated topic, but when I get bug reports about an accessibility issue I tend to drop everything else and try to fix it.

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.)