It is counterproductive and anti-intellectual for a historian to "sanitize" history. One of the reasons to study history is to learn from it. If we provide only a nice-nicey view of history it is basically impossible to learn anything. We use innuendo instead of plain facts, perhaps, but that is just sweetener in a bitter pill.
Historically bad things have happened. The bible, for example, has some pretty brutal sections. Does a "christian" educator also want to sanitize that.
If you sanitize Huckleberry Finn, for example, the story loses its point entirely. It is what it is.
I don't think there are any black people in America over the age of two who aren't familiar with these terms and how they have been used. Sanitizing the history of racism only erases their experience to make others feel good about themselves.
We need to learn to behave better. Pretending that we haven't behaved badly doesn't help us get there. The fact that some dehumanizing terms are still used today is the problem, not that that we find them in the historical record.