Both Marcin and Lea are ignoring users who have automatic sunset-to-sunrise dark theme switching.

This is not a novelty but a built-in feature called “Auto” Appearance in MacOS, iOS, iPadOS. Similar feature exists in Android and KDE.

It’s in TFA, just a few sentences in.

Isn’t the article about how to best deal with the UI for letting the user indicate that the system should decide? Which covers your case.

Thanks, I missed that!

But still, the article continues to ignore that setting, doesn’t it?

The light/dark theme toggle is for a small fraction of the people who genuinely care about controlling the theme to be "right for them" and not just whatever.