I see what you’re saying. I will not speak of the American decision to drop the atomic bomb as I feel there are a mess of competing interests and parties involved, and I don’t know what to believe, ie: avoiding the death toll of invasion, showing the soviets the power of the atomic bomb, ending the war before the soviets could aid and therefore influence the aftermath of an invasion, etc. However for the sake of argument let’s say that it was done in a utilitarian fashion to reduce the overall death toll. If this is the case then I think we can say it was justified, while also acknowledging the horror of it.
To your second point, I think it is good to differentiate between the people and the government. The government should apologize full stop. However for those interviewed in the article, especially for those who were kids at the time, I imagine the horror of the bomb is a lot closer to them, also given they were coming out of movie about said bombs production.
Yet, I don’t know if there exists a general consensus in the Japanese population about the atrocities committed by their military during the war. I would imagine they know some of it given that Japan is a westernized country with the free press, yet often times past wrongs are left out of public school curriculum. Especially when like in the case of the Unit 731 the United States was very interested in their results initially.