A well designed dark mode UI is just as readable as a well designed light mode UI. The issue is a lot of designers design light mode then just try to invert for dark mode rather than actually designing for dark mode. I'd imagine your post would exist for light mode if we had started with dark mode as the default.
A lot of software is dark-mode first but it's still not right. Good dark schemes are just really hard to design, there are just too many nuanced differences. Color perception is maybe 10% of it. Typographics, line thickness, optical balance, accounting for massively increased contrast, antialiasing, layout, picture rendering, absolutely everything should be done differently on dark backgrounds.
And it depends too much on your environment, the type of display, and its pixel density, unlike in light mode which is way more forgiving to external factors.
> A well designed dark mode UI is just as readable as a well designed light mode UI.
This could be correct if astigmatism was rare.[1]
[1] https://medium.com/@h_locke/why-dark-mode-causes-more-access...