Very easy to say that they can't be blamed for sins of their ancestors.  But, if there is any truth to what you say, why aren't these "pacifists" denouncing the aggression of their ancestors?  Why does government ministers regularly pay official visit to shrine containing aggressors, rapists and convicted war criminals?  Why aren't the Japanese ceding territory to their former foes?

Imagine the uproar if Angela Merkel wore a swastika or praised Hitler. Or, in 1990, Germany didn't renounce its claims on Polish land.  Today, Japan continues to have an emperor and worships WWII criminals.  Islands are still in dispute with Russians and Chinese.  And you want to call them pacifists?

Easy for aggressors to forget the atrocities and the sins of their fathers, especially when they are enjoying the fruits of their sins.  Not so for the victims.