If you grow up in America, you are inculcated (or you were) with the belief that we are the good guy. Always. Everywhere. At all times.
When I got to Vietnam, long before I ever read any history, I encountered the OGR. That’s short for Only a Gook Rule. That rule, which had been in Vietnam as long as Americans, meant simply that if it was oriental (language of the time), you could kill it without worry. It lasted until My Lai was revealed.
That’s where I lost my good guy virginity.