That’s part of the process of resetting a property for the next reservation. It’s not bizarre, it’s literally what Airbnb landlords do (or sometimes hire other people to do, but that lowers margins)
"Why would an airbnb host enter the unit to take trash?"
Not every airbnb host has a professional cleaning staff, and some of those who do may sometimes wish to check the status of their property. I don't find anything strange, let alone "bizarre".
Does the un-regulation cut both ways? A landlord usually needs to notify tenants 24hr in advance if they're going to enter the property. Does an AirBnB host need to follow any similar rules? It's not like the renters have a lease, it's not their residence.. Do they have any rights to privacy or notice at all?