We're All in 'Dark Mode' Now
theatlantic.com
theatlantic.com
I think it's really as simple as: dark mode looks cooler? It's different and tech-y and aesthetically appealing?
Studies show reading natural language text for understanding is better with dark text on a light background.
I really think it just comes down to what you use first and what you've learned to be productive in. And for coding, the legacy of monochrome monitors and terminal interfaces is just really, really strong.