I'm not black. I am Mexican- and Jewish-American. I generally pass, probably only 10% of the time people realize I have Mexican descent, 35% Jewish.
I've been in the middle of conversations in which some participants did not know they were in the midst of (clutch your pearls) a "minority." When they used shitty words, it was because they had shitty thoughts and they had shitty intentions. When I heard my neighbor describe someone else as a "sp!c," it was not a term of endearment. He was minimizing that person, using the word in a way that said this person deserved no respect. It was an act of racism. When I heard people used the phrase "Jew down," I knew there was a racist meaning ... especially when they suddenly collapse in embarrassment when I revealed I was Jewish. There are dozens of others times when people frankly revealed themselves to me.
What HR did to Walter Mosley (whatever it was) was not "woke" or "political correctness" gone awry. It was CYA. Perhaps Mr. Mosley had some good reason to use the n-word, talking about his experiences as an African-American man. Human resources has an obligation to make sure that there is an atmosphere conducive to work, and that abuses occur that disrupt or affect performance. Because Mr. Mosley quit, we don't know what HR's intentions were. If any employee, including African American, were using the n-word casually, it should be investigated.
You don't need to use ethnic slurs when describing people. You don't need to defend the use of ethnic slurs in public. When you do so, you are defending racism. If they are on the tip of your tongue because your friends always use them, it's probably because they are accustomed to using language to demean and insult people of other races.