As for the other points, its largely subjective but I have dark mode enabled in every app that will support it. On windows, I run the experimental build so I can have more complete dark mode support, and enabled the half baked dark mode in sql server management studio. All my IDEs are set to dark mode, because eye strain is a thing and for me at least dark mode is much easier on the eyes.
Personally, I don't think there is an ideal solution to match all scenarios. There are some applications, where light on black may be superior, and others, where it's the other way round. Empirically, for content-heavy, lengthy text we had a few trends for light on black in the past (e.g. "cool web design" in the late 1990s) and reversed from this soon each time. For an example, I much prefer reading HN comments as-is as compared to a hypothetical dark mode UI.
This isn't entirely true; many CRT-based terminals have phosphors that dim slowly. If they used a black-on-light color scheme, the letters would be washed out a for a lot more time than light-on-black. Light-on-black hides other defects more (like a not-quite-centered horizontal and vertical hold) and may possibly use less power (since the electron gun is off for more time).
I think the point they are making is, why would we have ever moved away from the technologically simpler option if it also happened to be a better design? What made us get rid of terminal colours in favour of black-on-white, when we could have just improved the design of the white-on-black colours?