The rules need to be changed ASAP.
Treating Covid like the bubonic plague is the problem, i.e. when a rider who won a hard stage (Vlasov) is forced to retire the following morning due to testing "positive" for a sickness which evidently had zero effect on him, it becomes unworkable.
By nature, Cycling is an extreme outdoor activity in which its actors will occasionally get sick or injured. This is part of the sport. But you just can't kick them out of the race like this for so little.
So Vlasov is out, jeez. Yeah, it's too much. Imagine Roglic or Pogacar withdrawn from the Tour due to a COVID test (the latter actually was withdrawn from FW due to a false positive).