In the words of Charlie Warzel, the author ot the piece:

"The idea is simple: If low-risk people don’t socially distance, then the entire containment process is not effective. Generally, there are fewer high-risk individuals — the sick and the elderly — and they don’t tend to move around as much as lower-risk individuals. Therefore, it’s more likely that a low-risk individual will expose a high-risk individual to the virus."