@Tiffany539 If you had done a search on this forum, you would find thousands of posts about the faulty rating system. Hosts have been railing about it for years but Airbnb obviously doesn't care. As you found out from your guest, Airbnb leads guests to think that they are leaving a good rating if they rate 4*s and "as expected" if they leave 3.
In the real world, there is nothing wrong with "Good" or even "as expected".
It is Airbnb's intention to keep hosts stressed out about their ratings and reviews, so they will let guests get away with all sorts of bad behavior.
I wish they would do away with the ratings entirely, as they are totally subjective, and only have written reviews, which at least give information. No one has any idea why a host would rate a guest 3*s, or a guest rate a host 3*s, because there is no explanation attached to it. One guest might rate a place that's a 20 minute walk to the beach 5*s, because they like to walk and consider it good daily exercise. Another might rate it 2*s because they aren't used to walking anywhere and consider it inconvenient. So ratings have very little, if any, value, IMO.
As a home-share host, I have interaction with my guests during their stay and often educate them a bit about Airbnb's rating system. They are shocked to hear that Airbnb considers 4*s to be a fail for hosts. Most guests have no intention of tanking a host's business.
Some hosts put a short explanation for guests in the unit if they host entire places. It's just important not to word it as if you are asking the guest to rate you 5*s, which can totally backfire.