How about when someone posts an egregiously offensive comment, instead of editing it for language or deleting it entirely from the thread, remove the entire content of the message and replace it with an italic

"Comment Removed By Moderator"
or "Comment Removed"

That way people can still follow the thread, and people won't have their individual words cleaned up. It's more take it or leave it, and maybe would help with some of the issues that moderators have intervened in before: swearing, racism, sexism, etc on the board. Basically, your comment is either up to standards or not. If people have a lot of comments left on threads that say "Comment Removed By Moderator" it would also speak to something about the poster.