I think the article does need some more editing to explain, with sources, (a) where the different names are used (b) whether they are actually referring to the same food. For example, this article in the Illinois Times says "In the mid-Atlantic coastal states and New England they’re more likely to be called scallions; everywhere else, they’re green onions" which doesn't imply that "scallion" is used by "most" English speakers as the article now says.. "Scallion" seems to be used in Northern Ireland, but not in England in my experience – there they are called "spring onions".