Correct, He could always have allowed it, but the contract with owners,,and the reasons owners have booked with him and paid him a decent fee...was so they didn’t have to do anything more once the reservation was made,
In this situation, with so many renters not being able to go, he has taken the hard line, even when owners have said they would reach out to a renter and get them rescheduled.
That is why your situation is so difficult because he hasn’t been very renter or owner friendly since this started.
Maybe you will get lucky and he will be in a different spot and change His current practices!