This is just the problem @Alienor-and-Piers0 , @Airbnb are not giving a **bleep** about the hosts. They refuse to change their policy to be reflective of a country by country basis. Here in the EU, most countries can travel between themselves as well as a handful of other countries in the world. So why if they guest have no restrictions (physical, governmental or legal) are Airbnb offering them 100% refunds?
We all understand when the situation hit the hot point in March, that there really was no other choice but to offer cancellations, but now when so many borders are open and travel has returned, there is no reason to continue with the policy.
Then as you say, we are not even informed that there will be a policy change. We are only informed, when a cancellation email arrives.
It is just a total lack of respect for the hosts. But this is what happens when you take a small 'local' idea and grow it into a multi-billion dollar company. You become an arsehole overnight like all the other bigwigs.