There are lots of reasons why the Asian mass slaughter of civilians has been ignored, many of which Iris Chang outlines in her book on Nanking. One of them that she doesn't mention is touched on by the author of the "Sun" piece--that it was an almost continent wide holocaust imposed on the citizens of many countries regardless of ethnicity. Further, unlike the European holcaust, it wasn't centralized--there were no pictures of impossibly gaunt survivors, mounds of skeletons or crematoria smokestacks in Southeast Asia, China, Korea or the Philippines. It was simply less dramatic.
If only I was a teacher.
All of this suddenly reminds me of my girlfriend telling me how her mom
generally disapproved of her and her sister listening to J-Pop music and watching anime, not harshly, but as a rather religious woman, the nagging seemed to stem from the "everything-but-The-Book-is-bad-for-you" ideology often associated with the Right, as the disdain encompassed just about
all forms of music and media. But there might have been something more to it. Both parents were
passively dismayed when my girlfriend bought a Honda as her first car. But they also warned her to never buy Korean cars, and they're Korean! Later, out of a general curiosity, I asked my girlfriend if her grandparents had been forced to adopt Japanese names, as they'd lived through the occupation. She didn't know the answer, as few in the family openly mentioned it, but in asking her parents about it, she found that their parents had, in fact, been saddled with Japanese names, but that was about as much information as anyone could give her. She found this out only weeks after her grandfather passed away, several years after his wife, both of them taking stories that might have needed to be told to the grave. I think some Asian cultures—perhaps moreso in the North American disapora, I don't know—have almost been complicit in leaving an uncomfortable past behind, as it were. Certainly it's not the same thing as the blatant revisionism practised by the Japanese to this day, but it doesn't help that disaporic generations three and four times removed from the events are probably better educated about German atrocities than they are about those that befell their own people at the same time.
The west needs more Iris Changs.
Quite unlike the standard imperialism position, usually couched in moral platitudes like "we are bringing civilization to savages" or "saving the people from 'terrorists'".
Nice one.

It would seem that no human being is in any position to decide who committed the worst of the atrocities, or who was more/less at fault. The U.S. is certainly in no morally superior position whatsoever.
Perhaps they might be if they'd shown up to the parties a little earlier instead of having to be
provoked into it.

Seriously, though, you're right, but while I'm not so sure a condemnation of Japanese behaviour
prior to and during World War II is an
automatic dismissal of similar acts perpetrated by the Americans, from what you say about the Sun writer, perhaps that's very much the case?