Join the club. I sometimes get 4’s for value. The comment on the last one was “Maui is so expensive!”
Well, no duh. You should see my cleaning, maintenance and repair bills.
The only solution I can see is to somehow educate guests so that they will do better in the future. Emphasize to them that information known before booking should be what’s expected, and that marking down the host for an already-known expectation is not appropriate. This would be besides the usual teachings about how 4=bad in AirbnbLand, unlike almost all other rating scales on the planet.
I actually think that lately, some guests are coming around and seem to understand some of these points, and their ratings are starting to reflect that.
Also, Airbnb will stretch to let a guest’s observations stand. They will only remove reviews that violate specific policies. Otherwise, the answer will be “Well, our guests are allowed to express their point of view, and bad reviews are not necessarily invalid reviews”.