I have never understood this. Black text on white backgrounds is fine at night, maybe you should stare at screens more or something? Or use something that adjusts brightness to ambient light, like most phones do now. I personally do not like all this low-contrast nonsense, clear and legible is the way to go.
I think the comfortability of contrast is subjective. I have several coworkers who use higher contrasts themes and swear by them, but my eyes start to hurt if I look at content that’s too high contrast. White text on black is by far the worst for me, but I know people who find that very readable.
Yet I have only ever heard of people complaining about it recently, when GUI designed started debasing itself by making everything web-based, and zoomers started demanding dark mode everywhere. Before that, and in my lifetime of computer nerditry dating back to the mid-90s (on self-luminescent CRTs!), I have never heard of people intentionally turning down the brightness or complaining about contrast of anything, whether its a tube TV or computer screen.
Which makes this whole preference for low-contrast incredibly suspicious. Like it was another one of those learned 'ailments' that spread around society like a shitty meme.
My phone is always on low brightness at night, but for some reason my monitor is always at 100% without question, which means light theme during the day (to match paper/pencil in front of me) and dark theme at night because it is otherwise too much light. Then one day, I tried a light theme at night at 50% monitor brightness and my eyes relaxed immediately. I realized that I have been squinting constantly to brace against the maximum brightness.
The usual advice is to instead increase ambient/room light but I have the room light set perfectly for writing and reading on paper.
Decreasing the brightness reduces the contrast which also decreases the readability of it. A dark background with light text has both higher effective contrast and less light hitting your face.
