This is the one part of the TOS that addresses that issue:
8.2 Booking Accommodations
8.2.1 You understand that a confirmed booking of an Accommodation (“ Accommodation Booking ”) is a limited license granted to you by the Host to enter, occupy and use the Accommodation for the duration of your stay, during which time the Host (only where and to the extent permitted by applicable law) retains the right to re-enter the Accommodation, in accordance with your agreement with the Host.
I think it’s the part that says: which time the Host (only where and to the extent permitted by applicable law) retains the right to re-enter that needs to be looked at closely. E.g. what your local laws say about it regarding STR. It’s likely in with the hotel law stuff. Most of the time it is legal to enter a STR though people (guests) spout off about it in a very defensive way and believe that they have certain rights that are really only reserved for long term tenants. You would need to check your local legislation on this but it will differ from landlord-tenant law. Airbnb seems to have made it clear their viewpoint on it in noting “to the extent permitted by applicable law”; however, it may be interesting to call and ask them. Of course if you call 3 times and talk to 3 different CS, you will likely get 3 different answers. But if you do call, I’d be interested in knowing what they say. Meanwhile, I’ll dig around too
Edit to add: I’m not addressing privacy issues or ethical issues but am also curious what the official standard is, if there is one. The fact that the TOS mentions “applicable law” makes me think they don’t have an official stance.