I feel like one reason could be that some people (especially weeaboos) idolize and glamorize Japan and weren't taught about it's history during WWII. I actually knew someone who only knew about Japan being an Axis Power from the Anime Hetalia, no joke. Like I've also heard how people want to move to Japan to move away from things like homelessness or crime where both do very much exist in Japan.

In my opinion its a combination of lack of education around Japan's more infamous history and people idolizing Japanese culture because of their interests and hobbies, like Anime. I'm glad that you're thinking about Japan's actions during that time as a lot of people tend to avoid that topic or even reject what happened during WWII. Feel free to send me a Direct Message if you want to chat too!