I think the person you're responding to already knows that and the implication of "the bad things they've done" is that they mean "the bad things their nation has done." It's a problem that Japan (or more specifically, Japan's government throughout the years) seems to have more than other nations because it's historically made a big show of its status as the only nation to ever suffer the use of nuclear weapons, and has plenty of memorials and museums to remember the event, while militantly denying, internally and externally, its own history of incredible violence and cruelty towards neighboring countries.