When I lived with a Japanese family in Hiroshima for a month in the late 90’s, I never encountered any signs like you describe. Things may have changed since then of course, but my general impression was that Japanese people were incredibly kind, thoughtful, and considerate of others. I did have a random old lady drive up and start screaming at our group of American students at one time totally unprovoked. She looked old enough to maybe have lost people in WW2. But that was the only time I was there where I ever experienced any open hostility.