I just want to add a perspective on this that I think might be useful.
If this was the real world, I would agree completely with femtoRgon's answer. Concepts like race and gender (which tend to have slurs associated with them) are essential to understanding both ancient and modern society. So if a historical account uses a slur, it's important to understand why that account uses a slur, and for the slur to not be censored. I might be getting ahead of myself, but I also think the role that concepts like race and gender played in history will help explain the role of such concepts in the present day.
But this isn't the real world; it's the internet. Most people today have (to put this as vaguely and as mildly as I can) strong opinions about gender/race. Given the anonymous nature of the internet, having a productive conversation about gender/race is infinitely more difficult than having on in real life.
I personally don't like to talk about race/gender on Stack Exchange, even though Stack Exchange is very well moderated. I'm writing a post (probably multiple posts) about race on my blog, but I'm only doing that because my blog doesn't have comments, and because I have admin powers on my blog.
If you all want to discuss gender/race on this site, then go ahead. If you can pull it off, then I will be incredibly inspired and impressed. But I think you underestimate the difficulties involved in discussing gender/race on the internet.
This meta discussion was prompted by an edit that censored a racist slur (which was quoted from a historical account). However, because only some of the letters of the slur were censored (e.g. sh**), it was still possible to tell from the context what the slur was.
If this was real life, I would revert the edit and explain why it's necessary to keep slurs contained in historical accounts uncensored. But this is the internet; that conversation is hard enough to have in the real world, and (from my experience) virtually impossible to have on the internet. So the current situation -- the word is partially censored, but it's possible to determine what the word is from it's context -- isn't that bad of a compromise.
There are some incredibly brave people who talk about race/gender online. All of them do so using a personal blog, and even then they receive violent hate mail on a regular basis. If you want to talk about race on Stack Exchange in a meaningful way, then I think the entire internet would benefit. But you need to think about what that entails. In effect, the moderation team (and the community) would have to make a huge commitment to make this work.
If you want to make that commitment, then that's great. But you should understand what that commitment entails.
I don't really know if this changes anything. But there's a long history of anthropologists/folklorists ignoring sexual elements in the cultures that they study, and then making false conclusions about those cultures because they ignored the sexual elements. I guess that's something to consider in this discussion.