I mentioned that that is not a guarantee. And that if his reasoning was the slave trade, then there are issues with that line of thought. Because there are.
I made a plea for empathy and suggested that just because a society has made mistakes doesn't make them "evil".
You decided to argue the semantics of me saying "one immoral act".
I was the one arguing for a view of history that isn't some "Manichean battle of good and evil". And I don't see how any of my posts do anything but that.
People who say "there should be a rule" don't really want to argue points. And maybe if you don't want stupid words in your mouth, don't say them.