How should I handle this extreme family argument?

Myself, my husband, and our 3 children went to my mother in laws house for a work weekend. Everyone arrived on Thurs or Fri to work except one sister. She arrived late Saturday after all the work was finished with her husband and daughter. They began drinking the moment they arrived (no one else was), and by later that evening he began telling his wife to sit down, shut up, cursing very profanely, and saying he didn't give a *uck he is from Newark and this is how we do in Newark. (He hasn't even been to Newark in over 10 years). We all are very hard working people, while he has no job and doesn't even try to find one. We just took our families there for some fun. After moving from room to room and his bombardment continuing for over 15 minutes and my children being woke up by his yelling and cursing I said "Hey Mike could you please not talk like that I am not used to being around men that talk like this to women". At that point an all out brawl started which I ignored up until he called me a stupid as* bitc*. My husband and I both came off the porch ready to fight along with the rest of the family. He 11 year old daughter jumped in the middle crying and screaming Daddy please Daddy no Daddy stop. I could tell she was used to him doing this to the mother, and that scares me. After we came back inside the remark was made to me that I should have stayed out of it because they are black people and that is how black people talk to each other? (By the way I am white) I have been around nothing but black people my whole life, and have never seen anything like this happen. My feelings were that if he was in a group of people and was making others feel uncomfortable then he should be asked to stop. Did I do the right thing by speaking up or should I have just continued to listen to it and allow him to talk like that in front of my children?