Argyle King
Legend
You proved the existence of the concept, and I've never disagreed with that. You have yet to prove that this is a general rule observed by society. I still don't think it is. More even so, as I've stated earlier, I don't even think most of society cares about that. I know that I don't. And I say that as a person from mixed ancestry living in a third-world country (not that I care about the concept of "place of speech", but maybe you do).
I think saying it's a "general rule" is hard to quantify because it is an issue which does not have generally agreed upon lines. Obviously, things like black face are generally accepted to be negative. However, there's not a good general way to define what should and shouldn't be culturally offensive for a society comprised of multiple cultures as a whole.
That being said, I lean toward agreeing with Jester that cultural appropriation is something which receives a lot of attention. It's still an evolving societal discussion.