all good things in moderation.
They could easily have used a light grey, which will reduce the contrast slightly, and thus ease eye-strain. As someone who has sat in front of a computer all day before, trust me when I say that the stark black-and-white will burn the eyes if you are trying to read for a long time. "White space" is a term from when people used typewriters on white paper. You don't need to use pure white for the "white space" your research is talking about.
You are saying that white space can be good, and should exist. The original poster said there was TOO MUCH. The 2 can both be true.
Oh, and research has also shown that the use of highlighting and of borders can be more intuitive than simple white space for indicating the organization.
1) If you have a solid line between 2 things, the brain treats it as a break, and will consider the 2 things as separate. White space leaves it to the mind to IMPLY that the things are separate.
2) If you have 2 paragraphs in a box of a "highlight" colour, then the brain will automatically connect the 2 paragraphs as a single "section" or "group". If you are simply relying on white space, the brain must actively work to sort the information and track which group goes where. When you are fatigued and can't focus very well, a highlight will be clear about grouping, while white space will make everything blur.
