So to be clear, Airbnb is helping volunteering hosts to provide their houses for free, right? If so, this tweet is misleading, from its wording I expected Airbnb was compensating the hosts.
They should take it a step further and pay the hosts double to accommodate refugees. After all, if any guests are the sort to hang around the house all day instead of seeing the sights, it's refugees. They don't have sight-seeing money, and they have more luggage than normal guests. They're kind of stressed out too, due to being refugees.