I doubt the response to racist remarks would have been the same in the 1800's
In the 1800 people of color did not have a choice to like it or not. There are still older people who use the words Negro and Colored. Younger people are less likely to use any word representing race. I had a friend who when he went to visit his friends who were Native he would say I am going to visit my Indian friends. I would never dream of saying I am going to visit my White friends. But that is his mentality. I am 79 years old and was not raised in the atmosphere where people were identified by their race.
None of those terms are equal to the term Ni-gg-er. I understand that older people are slower to adopt currently acceptable standards, and some might never be able to. However, a politician representing people in what ever position is required to make that step. Otherwise, they are just not suitable to fill that position. I'm not quite that old, but I was raised in a white only town, and used that term exclusively as I grew up. At that age, I didn't know it was offensive. When I was old enough to interact with the world at large, I realized what was acceptable and not acceptable. Our politicians are required to do the same.