Hi Emerald2 and welcome to Cruise Chat.
We were supposed to go on a cruise that included Casablanca, too. I can't remember if it was on Royal Caribbean or Celebrity. We chose that cruise because of Casablanca, because we had been to most or all of the other ports already. Our cruise also eliminated the stop in Morocco, but the itinerary change came many months before the cruise, and we ended up canceling and doing something else. It was our third attempt to go to Morocco; something had happened each of the first two times, too. Those first two were not cruise related. Sometimes I think my visiting Morocco just wasn't meant to be!
Usually, an itinerary change like that is not really the fault of the cruise line, but rather, is because of some change that the country involved has made. Sometimes they decide to limit the number of cruise ships in port at any one time, sometimes it's a tax issue, or whatever.
I truly understand your disappointment, particularly this close to cruise time. Are there other ports in the itinerary to which you have not yet been? Sailing on the Century will be fantastic, wherever she goes. This will just be good incentive to plan another trip to Casablanca at another time...