It's not surprising at all. All of these review-driven P2P marketplace businesses end up with the same problem. After the initial phase of early adopters that offer generally high quality products, a flood of fake or low-quality listing tries to squeeze money out of the platform. These people are not listing their homes on Airbnb, they are trying to make a living by extracting as much money from the platform as they possibly can. They don't care if they're banned or reported. They'll just make a new fake account. Low ratings? No problem, just pay for some fake reviews.
The same is true for Amazon and other marketplace business. It's overrun by Amazon FBA sellers selling cheap low-quality white-labeled Alibaba products. It's almost impossible to find real brands or high-quality products these days, unless you specifically know what to search for.
How to deal with it? Personally I've started going back to hotels to be safe. If I do use Airbnb, I do a lot of research on the host and reviews and assume the place I'm getting is 80% worse than what the pictures show.
Other examples: App Store app reviews, restaurant review apps and food delivery apps. Fortunately it's not a big deal if these are scams. It's just a few dollars. Sucks much more when it's your vacation rental.