Certainly denial of the facts of history can’t help a culture move on from a terrible thing like that. The fact is we do acquire collective guilt sometimes and governments do sometimes act to make things better. In Australia we had the apology to the indigenous people for the stolen generation (taking away children from parents). It was more about compassion than guilt and it did help many of the indigenous Australians to feel more accepted. Fortunately it was also followed up with actual policy as well.