Americans generally don't know or care much. A survey found that a significant # of American adults can't get questions about the American Revolution or other important events.
Is people not knowing or not caring about Japanese war crime something in the US only? (please delete this if it's offensive...)
American GI's were also subject to war crimes. During the Bataan Death March, Japanese would ride around in horses and lop off the heads of straggling prisoners. They made US soldiers bury their comrades alive. During the Nagano Olympics, there was a special on Louis Zamperini, who was a victim of all sorts of abuse and heard his buddies scream in mortal agony from germ experimentation.
However, the general public doesn't know or care much. Americans also seem to think of 60 years as a long time.
(During the tv special, they actually interviewed "The Bird" from the article. He claimed he was just being a good soldier.)
At the end of WWII, the Americans pardoned some war criminals and traded other favors to obtain germ warfare documenation recorded by the Japanese, including Unit 731. Japan's rapid postwar development was largely due to US aid as part of the containment strategy against the USSR.