Holocaust denial is illegal in Germany, as is National Socialism. There are no laws against denial of Japanese atrocities, nor was there a distinctive ideology to be banned following the war (as Nazism in Germany and Fascism in Italy). Most of the Japanese right wing is pro-American, but not all of it is. There are anti-Americans and apologists for Imperial Japan as well.
Another reason for the double standard is that Japan now benefits from political correctness as a non-Western, non-white power (though the Old Left hated Japan with a passion).
A final reason for going easy on Japan (despite the occupation) was because of the developing Cold War. Many Japanese who had been influential in the World War II government were pressed into service against Communism, just as East and West Germany were armed to the teeth by the Soviets and the West respectively.
I know that Communist China, North Korea, Vietnam, and Laos are more recent enemies and we have valid concerns about them (Red China most of all). But as much as I sympathize with Japan being pushed around simply because it isn't Communist (Commies never seem to do anything wrong), the fact remains that Japan was never de-"nazified" as were Germany and Italy and has never completely come clean.
A newly militarized Japan would indeed push back against our Communist enemies in Asia, but I'm afraid that things could get out of control very quickly. We could be facing the one remaining Axis power that was never ideologically purified.
I wish Japan well in its persecution by the Communists, but they must come clean and forswear once and for all their wartime ideology. Until they do, the danger will exist.
You could do better by asking America to forswear it role in this world where it invades and occupies relentlessly. we could simply have sunk our enemies navies, cratered their airfields, and smashed their armor. Instead we invade, occupy and set up corrupt puppet regimes. It's wicked hypocritical of you to go about demanding Japan continually hang its head in shame while your are not out in the streets hounding the American international globalists.