I understand why it bothers people to get an overall 4 rating unrelated to the 5 stars reported on feedback and written description. It happened to me recently and I had someone else staying here at the same time and they gave the bnb an overall 5 star rating.
The reason it is upsetting is that it seems to mean that even though I get five stars for all the work I did to make this a pleasant place to stay, they still don't think it is a good place to stay, because of some unknown, out of my control, mystery thing, that they haven't disclosed to me and therefore that I can't do anything about. The irrationality and insensitivity, of humans can at times give my mind a workout to deal with.
I am frustrated that Airbnb has not done the work to make their rating system a little more foolproof, a little more clearly demarcated, especially the location rating, which should distinguish the actual location from how to get to that location, both of which are clearly not in the control of the host.
I think they should have informational ratings that do not affect the hosts superhost status, as things that are not in our control, and yet that give guests information that may help them in their choices.