Weirdly, the only link I can readily find in the article to a source talking about the medicinal uses of cinnamon is an ancient text where I can't even readily parse what language it is in. https://www.biodiversitylibrary.org/page/463727#page/178/mod...
That's perhaps intentional given how up in arms people get if you actually discuss medicinal uses of plants. This article merely discusses the history of the monopoly on "true" cinnamon and some of the reasons for it, not actual medicinal uses.
I find it very weird how uptight people are about this. I mean if you know plants that get used in your diet can have medicinal impact, intentional ignorance on the topic seems to be a really bizarre policy to pursue. Yet that seems to be how the world mostly works in relation to such things.