I don't get the impression that Heinz is claiming they invented it -- they're just recognizing it and packaging it for sale. I don't see what's wrong with that, and I don't see it as "cultural appropriation." As usual, the WaPo is pushing a nothingburger in hopes of generating more divides among people in the U.S. They won't be satisfied until full-fledged intercultural civil wars break out.
Where do we stop? Do we have to close all Italian, Chinese, Greek, and Thai restaurants? Or only allow people of their respective ethnicities to eat there?
I've never heard a mix of mayonnaise and Ketchup called anything other than "It's a mix of mayonnaise and ketchup," but we used it in my family 60+ years ago when I was a kid. My late wife was from South America. Her sister-in-law uses it as a dip for hard-boiled quail eggs (delicious, by the way). When I asked what the sauce was, it didn't have a name. It was "a mix of mayonnaise and ketchup."