My experience was such that it wasn't that way at all. The camera was indoors but not in areas of the house where someone would be walking around without clothing, and they were clearly disclosed in advance before booking, and they were clearly visible in the home.
Some houses have areas where it is fairly reasonable that people wouldn't be running around naked, e.g common areas shared with others, or rooms with a large amount of glass open to the exterior of the home. And in some cases it might even be illegal for you to be naked in those areas if exposed to others.
I'm not defending it, I said I understood it. I have similar cameras in my own house, so why wouldn't others?
Further, expectation of privacy are commonly accepted to be more complicated than "indoor vs outdoor". To suggest otherwise is just hyperbolic pearl clutching.
My two examples above are perfectly normal situations in which expectations of privacy are lowered.