"Freedom of Speech" was originally primarily associated with political speech and open-ness in criticizing the government. The classic example people use to point out the difference between "Freedom of Speech" and a presumed right to say whatever we want to say is that we aren't allowed to yell, "Fire" in a crowded theater.
When I was three years old (many decades ago, as a little White girl), my little friend used the word in a kind of matter-of-fact way but without really seeming to know it was an ugly word. I'd never heard the word used before. My mother came out and said it wasn't a nice word, and it wasn't a word "we use in our house". My little friend said, "Oh, OK," and I would later go on to learn more about why that word wasn't just a "not-nice" word, but one associated with all ugliness of a history that should never have happened to human beings.
I think what my mother did was right, of course. I think when it comes to the littlest of children parents need to tell them it's not a word we use. Older children can then be taught why, when they're more able to understand. People often say, "It's only a word, and if it's used in a way that takes away its original meaning that diffuses it." I think the word ought to buried on behalf of those human beings who, themselves, were buried after a lifetime of having that word used against them in the way it was. It's true that it's "only a word", and because it is we have the power to decide which words we consider acceptable and which we don't.
I'm not in favor of suppressing or discouraging the expression of ideas (not even ugly, ignorant, ideas); but I think that one, ugly, word that has the history it does ought to be completely "snuffed out" of American vocabulary. To me, it isn't a matter of suppressing my speech as a White person. I don't think African Americans should use the word either - not in jest, not because they want to diffuse it, not for any reason. If we can't yell, "fire" in a crowded place that means there are some words in some circumstances that, if used, have too many negative and serious consequences to be used. I don't think it should be illegal to use the word, but I don't think keeping it alive benefits or respects the people against whom it was once used (or their descendants).
If there were an equal word and history for White people, I wouldn't want my kids to use it and "diffuse it"; because I'd want that particular past dead and buried so my kids could live in a new time. Maybe it's not for me "want" for people of a race other than my own, but I'd like to see, for young African-Americans, what I'd want for my own kids.