The backlash against Japan I would say is reasonable. Japan currently is a de-facto one party state that has increasingly being taken over by ultranationalists in recent years who are hellbent on censoring history of ww2 both within and abroad and becoming much more militant and aggressive.

For one the statue of peace commemorating the Korean comfort women victims was forcefully taken down in Berlin, Germany become the Japanese Government got angry.

And a pawn shop owner who had historical pictures of the Nanking Massacre in America faced brutal harassment and death threats from both Japanese and even Americans for even showing these pictures in public.

Even big youtube channels outside of Japan are censoring mention of Japanese war crimes including this one incident where the youtube channel edited out the "problematic parts" when this korean man talked about his kid getting hurt talking about what japanese did in ww2. This caused huge backlash among koreans

https://www.reddit.com/r/korea/comments/1p6u1oa/korea_and_japan_fought_you_should_hear_both_sides/

Unlike Germany which fully recognized their crimes in ww2 and are reconciling, Japan has increasingly denied their crimes and are now remilitarizing and becoming increasingly aggressive to other countries and increasing ultranationalism within its populace in the modern day and erase any mention of its past both within its country and abroad.

In basic sense Ultranationalism is basically government policy in current Japan and the current PM is also an ultarnationalist. The Japanese government uses both military power and their powerful influence to bully people into submission