The crux of your (and their) problem is this: Why, if, as you say, airbnb was being as helpful as possible from the get-go, did the victim write that second post?
That's it. You cannot have a claim to credibility until you answer that question. Even if that answer is, "she was paid off", the existence of her second blog post puts the lie to airbnb's (and your) claims. Either she's telling the truth, or they (and you) are. They are mutually exclusive stories.
Bringing Arrington's Arringtonity into this is a red herring. The story isn't about him. There are two involved parties, here, and you've aligned yourself with airbnb. The victim's story isn't being run through the TC filter; it's there for everyone to see. So far, the collective 'you' have not addressed it, refuted her points, or shown how the two accounts are compatible.
It's easy to hop on the "Michael Arrington is a sensationalistic dick" bandwagon, because he is. That doesn't address the issue, though, and it comes across as a deflection.