I've met plenty of veterans who fought in the pacific theater, and the last thing any of them would want to do is hang out with a bunch of nips. If that kid was sullenly shouting outdated ethnic slurs the whole time the Japanese camera crew was there, I might be inclined to believe this shit.
As someone who believes reincarnation is possible, let me just say that your past life is a lot like your sex life. You don't talk about it with everyone.