If they pay for this incident, they are possibly opening the door for the kinds of schemes people pull on insurance. You know, the whole "rob my place and I'll collect the insurance" schemes.
If Airbnb pays for this incident, they effectively become an insurance company. Maybe what they should do is offer some type of actual insurance package on checkout. This way, they are providing a much needed service and indemnify themselves. Making their customers aware of this possibility rather than pretend it doesn't exist would also help create a safer environment.
EDIT: Let me be clear. I don't honestly think this person should be left high and dry. What I am saying is, to a criminal, the headline "Airbnb pays for all loss and damages", is enough to commit the crime again. We know criminals of this kind bet on low odds, otherwise there wouldn't be so many obvious ones. You might think on the side of a flexible entrepreneur, but criminals aren't looking at how Airbnb is going to look.