A white theme, so what ?
Nothing more classic. I'm chilling, doing something, like programming, and, because I find something nice to share, I make a magnificent screenshot on my IDE. Until there, everything is fine. I paste the screenshot on a little bit of instant messaging service and...
Everything is fine.
Until the moment I receive those magnificent comments:
oH mY gOd, YoU wIlL bUrN yOuR eYeS
Or, with a little more context:
Me: What's wrong in this screenshot ? [insert a screenshot with something wrong, like a logic error]
One person, at random: The white theme
Anyway, I switch to being fed up because it's not the first time I receive the remark.
Why am I using a light theme ?
The question deserves to be asked. Why on Earth would I use a light theme ?
The answer to the question is so simple we could ask ourselves "Why haven't we thought of this earlier ?": because I'm working in a well lit environment and I see nothing with your pretty dark background without cranking up the monitor to it's maximum brightness.
Shocking, right ?
I have exactly the same issue in class, when code on a dark background is projected on a screen in a room with the front lights off: I see nothing, at least it's hard to see the code. We could tell ourselves "it's the size of the font", but even this may not solve the issue. So one sprinkle of light theme and "Ohhhh, we see something !".
By the way, making black with a projector is a bit complicated, might as well not make light and see nothing!
One other concrete case that wanders through my mind and that is able to help you "simulate" a well lit environment and its effect on a dark theme. I remember having the Firefox (I think ?) inspector set with a dark theme because why not. It turns out that you don't see a damn thing in the inspector's writings when you want to examine an element or see what's the networking doing when the website you're working on only has bright colors.
Now, replace the internet website and it's magnificent background with the sun that illuminates well a room and the inspector by the colors of your favorite theme displayed by your IDE. The effect should be similar.
The words of the end
All of this to say that light themes still have their place, whenever it's on a projector when we present a correction of an exercise in class or even on monitors we don't want to crank up the brightness.
The people who come to cry or meanly troll on the form instead of the content, when someone presents something on a light background, you should think a little further than the end of your nose and consider the environment where the person is in. You can also not say anything, it also works wonders.