Also, cast iron pans leach iron into food, and are therefore an effective way to treat anemia. Any one who needs a small, steady dose of iron can benefit from cast iron pans.
There's a lesson in that: journals print what people like to read. Everyone with a mild sense of chemistry already knows that you can't prepare tomato sauce or mulled wine in copper vessels, consequently such a paper will be rejected for being plain obvious. Stainless steel on the other hand, that's pleasantly controversial and you can debate about chromium and its oxidation state and essential nature and toxic concentration until the cows come home.
That explains the nature of the investigation.
Haemochromatosis is very much a thing, depending upon your genetics, as there are hereditary traits that will cause some folks to take up iron too readily. As your body doesn't have any means besides blood loss of getting rid of iron, it can ruin your liver and other organs.
I visited a castle once (modern ish) that used to be owned by rich folk who hosted lavish parties, they had a fully equipped French style kitchen, including all copper pans. The tour guide said the cleanup was terrible, especially for things like tomatoes or eggs.
And cooking acidic foods in cast iron ruins the seasoning, so anyone who uses it regularly already doesn't do that.