I learned about Franz Boaz in my linguistic anthropology class and thought about his warnings on ethnocentrism when he researched linguistic anthropology in the US. I had many experiences of cross-cultural conflict in my lifetime having lived on three continents, yet I didn’t have a specific word to describe this prejudice until now – cultural relativism. It’s the idea that we have to stop judging others based on our own expectations and experiences, i.e. our culture.
A clear example of this would be the ignorant well-meaning liberals condemning dog-eating in East Asia or unoriginal hipsters criticising others for eating insects, when in fact, they are using their own frame of reference to see others. A Kayan person might tell a Belgian that they are not attractive enough for no using neck rings and a farmer from Thailand may criticise an American for eating cows – the animal of labor in many developing agricultural areas. Although in physics the speed of light is the same in all frames of reference, in anthropology cultures are different in all frames of reference.
Any criticism coming from an individual who has performed zero-research on the subject is indefensible. The only way you can tell someone their culture is wrong is if you’ve become a part of their culture, understood their motivations, and still find no reason for the tradition to exist – which is never.