@Ann72
Sorry, if I used the offending word a little loosely.
However, I don't consider that I'm being 'judgy'. It's just my opinion based on my dealings with the Review and Rating system.
I don't consider 4 Stars as reason to ban guests from return to my home. I take greater stock by the contents of the Review. Anyway, it's all subjective. And as long as I've had a good experience with the guest, I'll accept whatever they write and rate.
I'm certainly not a zealot as other hosts, neither undertaking a systematic education program of Guests in Airbnb ratings; worse, the hard liners exercising 'the nuclear option from another host', as noted by another contributor to this thread.
Indeed, I've accepted returnees who only gave 4 stars. Likewise, those who wish to extend.
In both cases, they generally don't book again via the website as I'm not exclusively an Airbnb host, and as it's cheaper otherwise.
In sum, I'm largely satisfied with the Reviews & Ratings. Their principal reason to encourage others to book and fuel the machinery on the search facility. Beyond that, it's not worth the hassle.