It was inevitable that there was going to be a robbery or murder or some other major event that would cause a big stir for the company and challenge their response. To me the obvious thing in this case seemed to be to immediately contact the person, take care of all financial losses (to the excess in order to show they're taking the issue seriously) and then to use this case as a reminder to the community to be aware of potential dangers inherent in renting out your home and that while they can't take financial responsibility for damages in the future, they're willing to make things right in this case since it was a learning experience for everyone.
It would have been a reasonable response that would have made them look good. Instead they look desperate, political and selfish. It will hurt them more than it should.
I think in the end this is a huge opportunity for AirBnB. They are getting tons of press that they otherwise wouldn't get, and in this case their is no such thing as bad PR (I don't believe that to always be the case).
As more people are likely to be renters than rentees, this might for a short time limit the availability of accommodation, if renters are concerned about their property. But more renters will become aware of AirBnB and in the not too distant future people will remember something about a renter who's property got damaged and it was a big deal. That memory may actually be a good thing! The details will be forgotten, but it may be remembered that something happened and AirBnB had to take care of it.
As a home owner, if you are looking to rent out your place and your options are 1) a site you haven't heard of 2) a site that gained world-wide exposure when there was an incident regarding damage to a persons property, wouldn't you be inclined to go with the one that people are paying attention to?
Rock stars trash a lot of hotel rooms, nobody blames or avoids the hotels.