It seems amazing that you might not know, but in your case, may I recommend the film Blazing Saddles?

These days, it’s usually called the “N-word”.

The strange pattern of dashes you used suggested something else. Why not just say something clear like "African Americans" or similar?

I did know. That was an "um, come again?" not a "can you repeat that?"

Your comment literally reads as "they used to tolerate refusing service to (slur)s." Not only was it totally inexplicable to use the slur in the first place, you didn't qualify it in any way. No quotes, no "people they called," nothing. You just used it. Absolutely insane.

You don't have to use quotation marks for something to be a quote. It's not insane at all.

Yes, you do, that's how English works. If I insult you I don't get to say "well, it was a quote" after, I already insulted you.

To black people who they referred to via a racial slur.