I don't disagree that the situation sucks for landlords if their tenant breaches the tenancy agreement and uses Airbnb as a tool for sub-letting. This of course

I don't disagree that the situation sucks for landlords if their tenant breaches the tenancy agreement and uses Airbnb as a tool for sub-letting. This of course also places the tenant in breach of Airbnb's TOS too. But you're now suggesting that this injustice to landlords justifies harvesting Airbnb's user's personal information and then selling it? That's morally and legally questionable any way you look at it.