Sanitising History?

I thought I'd use this brief break from my fully booked timetable to post an interesting story my friend just told me - I think it illustrates really well the effect keywords can have on the perception of images:

While I was studying for an MA History & Theory of Photography our class was given a tour of a picture library’s historical archive. In one particular room several people were scanning and others were captioning, old images. We were free to talk to the employees. I looked over the shoulder of one of the keyworders and asked her what she was doing. She said that she was PC'ing the keywords. I asked her what that meant and she said that some of these old images have captions and words that we can't use, such as the N word, so I'm re-keywording them. I told her that you are re-writing the past and she just looked straight through me, with the look of someone who has been keywording continuously for hours on end. Later I brought this up with the manager who had given the tour. I said that you are sanitising history, you are changing it to make it more palatable and he just shrugged his shoulders and said that unless they ‘corrected’ these images they wouldn’t sell.

Historical accuracy and commercial sales aren't easy bedfellows but I cannot but wonder that if by making captions and keywords more PC we are promoting a kind of deliberate social amnesia? Shouldn't we learn from the past rather than cover it up? Photographs have been retouched and manipulated from its inception but I think that my friend's story is a good example of how metadata can also have a subtle yet crucial part to play in the way in which we understand images. Good and bad comments are welcomed.