Nobody knows how to give a proper rating these days. Either something is 10/10, or it's 0/10. Most people are not "Local Guides" on Google Reviews for a reason. Nobody will take the time out of their day to review something if it's just mediocre. They will only do it if it's flawless or completely trash garbage. That makes sense on a personal level, but it makes it very difficult to gauge whether something will be a good or bad experience.
The real story comes in the 2/5, 3/5, and 4/5 star reviews. Those numbers get into the nuance of an experience and let you know where it falls on the below-average to above-average continuum. Unfortunately, some business owners are psycho and get extremely pissed off when customers give them anything less than a 5-star rating. One of the industries that hold itself to the highest standards is the vacation rental industry, especially Airbnb owners.