Host Declined Reservation, But Room Still Listed

I wanted to book a room for two nights and found this listing that I liked. I was under the impression that if a room is advertised it should be available, so I went ahead and sent in my booking request to the hosts through Airbnb. I have verified myself on Airbnb through my driver’s license. This reservation is during Christmas when prices go up within a few hours. After almost 12 hours, the host responded and requested I cancel the request as she has family coming over. I went ahead and cancelled, but I still saw the listing available on Airbnb. Why is it still up if they know family will be taking up those rooms. Is this not discrimination?