Is usising the words jacks or blacks in this type of incident be a reason for termination

I am or was a food server, I am caucassion, on this particular day I was informed by Host who is black that I was have guests at table 14. I said to him if their "Jacks" Aka "Jackasses" ( this is what I call or refer to guests that are disrespectful and rude.) I will kick your ass, (all of the crew members joke around with each other). After I said that the host and another coworker who is black started laughing. The stood together for about 5 minutes laughing, at the end of my shift I was asked by the manager about an incident I had with the host about table 14, I had no idea that a incident even occurred, I was asked to fill out an incident report, and to come in tomorrow at 3:00 to talk the GM.

I was ask to tell exactly what happen regarding this incident, GM said I have 2 incident reports made by 2 employees that said that said if table 14 are blacks like table 16, I will kick you ass. I was terminated.