> No one is saying you shouldn't take the occasional walk while maintaining physical separation, in fact, that's what's being encouraged here.

It depends where. There are countries on lockdown where you are not allowed to go more than 100 m from your home even for exercise. If you live on a street consisting of blocks, then that means there are so many people at a time who would want to do their exercise, that you couldn't really maintain physical separation. Consequently, the authorities expect everyone to stay at home and e.g. buy an exercise bike. Also note that China’s approach in Wuhan was that no one may leave their housing block.

During walks, I believe the recommended 6-10 feet of separation is not enough. An infected person's perspiration / saliva / phlegm lie on the path, and, within 3 days, any subsequent passerby traversing that path could potentially pick up the virus along the bottom of their shoes. And, upon entering their homes, they will have brought the virus, this creating a whole new branch of infections.

The article referenced a closure of beaches. New York recently closed "parks." This is counterproductive. People need spaces in order to be socially distant. If you close all the spaces, they will not be distant.

This is not counterproductive. People have been mobbing the parks. The parks need to be closed. I live in Brooklyn and the groups I've been seeing until VERY recently are disturbing. When you close the parks, there's no where for groups of people to hang out. Need to go on a walk? Sure go on a walk and stay away from people. Not everyone needs to be on the street at the same time either. The reality is that in a densely populated city, parks or not, you can't find the distance unless you go out early morning or late at night and stay off the beaten path.