The author seems to confuse "better" and "more like others". The colors are a clear example of the latter, the developers didn't choose a light theme back then

The author seems to confuse "better" and "more like others". The colors are a clear example of the latter, the developers didn't choose a light theme back then because dark ones weren't invented yet or because computers weren't powerful enough for them. Things like the completion UI may be a different story.