Since all major phone, tablet and desktop OSs these days use flat UI anyway, I don't see how having night shift/dark mode to compensate for the eye strain caused by flat UI design is a misnomer. Now, if one or more still did skeuomorphic UI, you would be correct.
During the skeuo era, a lot of menus, settings pages, etc were dark anyway. The depth of skeuo also didn't harm anyone's eyes as much. People might see it as ugly (then why buy Apple at that time lol) but that didn't mean their eyes got strained. I don't remember eye strain until after iOS7, Mac OS X Yosemite, or Android 5.x Lollipop. These days I keep dark mode on 24/7.
During the skeuo era, a lot of menus, settings pages, etc were dark anyway. The depth of skeuo also didn't harm anyone's eyes as much. People might see it as ugly (then why buy Apple at that time lol) but that didn't mean their eyes got strained. I don't remember eye strain until after iOS7, Mac OS X Yosemite, or Android 5.x Lollipop. These days I keep dark mode on 24/7.