hostile work enviroment

Hello, my name is Ryan Gregory my question is about labor laws. This is the situation, i live and work in a small town in Oregon pop.3500 I mention this because unemployement is very high here(20%) jobs are hard to get. I work at a small casino owed by the local indian tribe (I believe this make me a federal employee). Today I had a fellow employee, a member of the tribe tell me in front of numerous witnesses that i needed to remember who i worked for (meaning the tribe) and that i could get fired if he wanted me too, i took this as him saying that since I was white i would lose my job. When I asked him why it had to go down that "road" he then came back and punched the table I was sitting at and tried to get me to go outside and fight. I went to my general manager and explained to her what happened. She then went and confirmed my side of the what happened. the witnesses both said I did nothing to provoke this and he addmitted to the whole thing. I feel he should be let go and I said as much. they allowed him to work rest of the day and said a decision on what action would be taken would be made at a later time. But I feel that if they give him a slap on the wrist of a three day supension instead of termination it does not send the message that this will not be tolerated. Am I wrong to say that if i could lose my job because of the color of my skin is that not a form of racisim in the work place? At the very least the threats create a hostile work enviroment. please give me some advice on this. thank you, ryan