The idea was that a route was posted, and everyone could ride out on their own, do the route any time during the day, and post to Strava for official record keeping.
But then small groups started riding out to the route together or ran into each other as they headed out there around the same time.... Doing it over a week might make more sense and reduce the possibility of people grouping up.
As for the social distancing, I don't know that everyone gets it. For example, they say stay in groups smaller than 5. And I frequently see groups of 2 riding together, which I guess fits that limit. But when one of those two goes out with 10 different people over the course of a couple weeks, it kind of eliminates the distancing and all 11 of them might as well be riding together.