David can claim whatever he wants, but his contract with owners says nothing about resorts closing:
The balance of funds owing to you is paid on the day of guest check-in. Reservations are NON-REFUNDABLE, so you get your money regardless of whether or not the guest checks into the resort.
The day of check-in doesn't change or go away and is not dependent on the guest checking in, per David's own words. Whether or not a guest can check-in is irrelevant with David's contract with the owners. I don't know what he has in place with any contracts between he and the renters. If David's was concerned with the resorts being closed due to a pandemic, then he should have put that verbiage in the contract with owners, so owners would know that they may not get their money in the unlikely event that happens; not pretend that it was there all along. They could have then decided if they still wanted to rent their points with David's. I haven't seen that verbiage yet in any of the owners contracts.
The owners are required to provide a verifiable reservation and keep that reservation in place by not cancelling it on their own or by compromising their membership. Owners are not responsible for something outside their control.......as much as David's may want them to be.