I spoke w AirBnB. Long story short that quote basically means nothing, except public relations to the guest.
Airbnb sends message "Hey, you have a post-May 31 booking. Extenuating circumstances policy does not currently apply. Do you want to cancel (normal terms) or recommit?
1. Guest cancels under normal terms.
2. Guest recommits. They can still cancel under normal terms, and would still receive benefit of an extension to the May 31 date. Ie. basically no change.
3. Guess ignores message. No change (is same as #2)