It is the word "must" that causes me trouble. Certainly the term "Creole" was used by many, might I say uninformed, writers to represent mixed-race people; however, as is clear by the Harpers Weekly obit, at least a percentage of people, including the newspaper with the largest circulation in the United States, knew the difference.
I must be honest and say, I ran this question past my wife, who has a great deal of French and Spanish Louisiana ancestry. She is a product of a highly-respected private girls school, five years of college and of course, uses excellent judgment, especially in the choice of husbands. ;-)
When I asked her what the term "Creole" meant to her she said, "Mixed race?". I told her what we had discussed and read her some definitions and she said, "I've always been taught that Creoles were mixed race, black people."
I'm curious if this misunderstanding of the term is pervasive and in other regions of the country or if this is specifically a "Southern thing".