Whatever people in previous times have done, good or bad, whether our ancestors or not, it is never a matter of "US", it is always a matter of "THEM". If we remember that it might take some of the heat out of our arguments. We've got nothing to be ashamed of and we've nothing to be proud of. It's not us we are talking about.

If as a society we are richer and others are poorer because of injustice in previous times, there may be a debt to be discharged, but that is another matter.