I sympathise with you all. I too go out of my way to provide clean comfortable and affordale accommodation for guests in three locations.
I'm not a "superhost" I do have many 5 star reviews and four stars as well, but it is those 1,2,3 star reviews from unreasonable guests which bring me down.
One recently gave me 4 star review and said she would have given me 5 stars but one saucepan lid had a broken knob! I didn't know it had this problem, and I have now fixed it, but there were several other pans with lids ( not with broken knobs) she could have used. So yes the review system is used for complaining about minut inconveniences.
Another woman walked in the door of the house and started complaining immediately for no real reason. Everything she was questioning was just as it should be, there were no problems.
@Cormac0I concur with your sentiment that hosts often are treated as door mats. and yes - Guest are expecting Hotel quality experience at youth hostel prices and the way the star system is set up, it reinforces this perception. I also agree with this statement.
It would be really nice if Airbnb would educate the guests again, about the principles of Airbnb, that they are actually coming to stay with people in their homes or renting apartments which real people have put together for their enjoyment, they are all sharing a piece of themselves as hosts.
I'll hang in there, after 23 years in the hospitality business I've seen it all I think.