For the same reason we drag YouTube into copyright complaints. You're correct in identifying that there needs to be some kind of fair balance here, but AirBnB makes a lot of business facilitating illegal transactions. I don't really think there are apartments in New York City in which running AirBnB
is legal, for instance, and yet NYC is one of their biggest markets. But yes, they also have legitimate, legal business. The trick is it is very difficult for landlords to monitor their properties for this kind of behavior, and also difficult to enforce action against it (getting proof can be extremely difficult, for instance).
Because much of AirBnB's business is flat out illegal due to zoning, property laws, HoAs and leases, I think requiring them to provide a better system for accepting accountability for the negative externalities they create is reasonable.
> I don't really want to live in a world where anyone on the internet can destroy my income via anonymous complaint.
That's not at all what I'm suggesting. I'm suggesting an easy way for landlords and others to determine if a property they own or one near them is being listed on AirBnB. After that there are a ton of avenues for justice one could take, and it would probably include, along with government/HoA response, a procedure for forcing AirBnB to take down the listing given proof of ownership or something, similar to DMCA, but this is not an unsolvable problem by any means. It's one AirBnB is choosing not to solve because it would destroy their business.