Agree that it's not technically an official study as it was never formally published in an academic journal or peer reviewed at all.
And you can't make the blanket statement that a certain type of diet is healthy for everyone just because it "appears" to be healthy in an observational study of people of only a specific race. What about the whole concept of ancestral diets and eating to your genome? I don't see the Inuits necessarily dropping dead of heart disease or diabetes like it's a plague, do you?
In fact, most of them do not develop heart disease or diabetes unless they adopt the western diet at which point, it DOES descend on them like a plague. You should mention something about that.