It's an interesting problem. I think it makes more sense to present it as it really is than to try and bury it. On one hand, it seems a little conflicting to reject prejudice and amorality but keep its products. On the other hand, trying to erase it from public consciousness seems like a disservice to progress. The "if we don't learn from history, it's doomed to repeat itself etc. etc." cliche. From that vantage point, it's really important to memorialize the dirty stuff.