Mostly it is a shaming tool to be used against whites, and particularly conservative whites for dressing, or in some way giving the perception that you are mimicking, in either a positive manner or negative manner, the habits or traditions of another culture. Never used against liberals, or persons of color. By inference, whites have no independent culture to be mimicked or appropriated.
The ridiculous idea that to, for instance, to dress up in a Halloween costume like Day of the Dead skull make-up is somehow stealing something from, and disrespecting Latino culture. Or another example, someone posted on a Trip Advisor asking if would be seen as cultural appropriation by Vietnamese to buy and wear a conical hat while on vacation. Short answer given? They couldn't care less about it, and would be highly confused as to why you were worried about it in the first place.