I might be old and crotchety, but that post is the opposite of a distraction-free reading experience. I count at least 6 fonts, 3 different background colors, 3 text colors, excessive whitespace on the borders, images that break that whitespace, animations, all pictures interrupt the flow of text...
The change of background colors is a deliberate design choice. The content is long and the background helps the reader, especially on mobile, to understand in which section he currently is.
It's a presentation in the form of an article. Same content, different medium.