I think this kind of attitude is what the author of the article is struggling with: assigning blame, tallying up the sins of each side to see who is the winner, this kind of debate is not useful - even if you don't intend it, framing things in this light will cause it.
There is value for everyone in discussing the nuances of dark events in our histories. But unfortunately we have a natural tendency to over simplify things into these highly polarized dichotomies, a vs b, in an attempt to make complex events easy to understand. Nobody alive today had a hand in these events, and while it's natural to feel things for our ancestors whether it's shame, pride or anguish, we would do well to distance ourselves like an alien observer when analyzing these events... the sins of our fathers should remain that way if we are to make progress as a species - I'm not religious, that was an accident.