Oftentimes, it can be important to keep the context of the slur, even if saying it in a manner would in fact be socially unacceptable. For example, if somebody is trying to call another person out for using one, photo evidence is useful. And partial censoring can also remove ideas from peoples heads that the poster is trying to say a slur for the hell of it.
FURTHERMORE, I would argue against that with the context of another rule. Take NSFW for example, cropping, and/or censoring the image is acceptable to the tos, yet you can clearly understand what the image was. I feel the same would apply to this