I don't see a problem at all. Like it or not, large portions have the world have decided to move on in a manner they feel safe. My brother (M.D.) was on the committee that recommended a local lockdown before the state ever stepped in. He and his colleagues have aged a decade in the last year as our town was hit worse than about anywhere (0.4% of our county population (not just cases) has died from it). He, and other on the medical staff will be at the start line of the first event they can do.

There are seven doctors in my immediate family who have dealt with COVID every day. At this point, every one of them would sign up for a race.

edit: One other thing. Obesity is one of the major risk factors for COVID mortality. Encouraging health and fitness was a good idea before COVID and still remains so.