Exactly, it seems much harder to blatantly vandalize the home of a like-minded person who personally welcomes you into their home, offers to show you around etc

Exactly, it seems much harder to blatantly vandalize the home of a like-minded person who personally welcomes you into their home, offers to show you around etc. than the fancy loft of some faceless traveling businessman. Also paying for something tends to give certain people a sense of entitlement. Of course none of this makes what happened to the poor person in this case OK or even remotely acceptable. Nonetheless, I think understanding why things happen is a good step towards coming up with a solution. Maybe if AirBnB can get some of the personality of the Couchsurfing community, it can get some of these positive norms that go with it as well. The trick would be how to do that without losing the low social barrier to entry they have now.