edit: I have gotten a lot of pedantic comments on whether or not yogurt is "exotic" and "middle eastern" (which is the deletion field you see before you) and I am majorly over it... it was a loose phasing to make it a more appealing question and get the updoots. Which apparently worked! Safe to say yogurt is not in the traditional diet of the bulk of European people who settled America in the 18th-19th century, that is to say German, Scottish, English, Irish, or even Italian, it it is a bit weird therefore that it has it's own private aisle with friggen genre subsections in the grocery store. In its marketing in America, it is framed somewhat as exotic health food, and this foreign health food framing has lasted in my brain, even though I eat about 50 oz of yogurt a week, no foolin, despite my ancestors stereotypically eating mostly oats and kasespatzle.
Yogurt began to be mass produced in the US in the 1940s[1]. It was established as a health food fad in the United States in the 1950s, in part due to the influence of Gaylord Huaser, a celebrity nutrition consultant and "natural foods" proponent. Establishing himself as a diet consultant to Hollywood celebrities in the late 1920s, he later wrote a series of bestselling diet books and was widely quoted in the media. He promoted yogurt as one of 5 foods that would prolong life in his work. By the 1950s, yogurt was well-known enough as a fashionable diet product to appear as a punchline in the 1958 film Auntie Mame. (The young protagonist briefly attends an extremely avant-garde private school, whose activities include "yogurt time".)
By the 1970s, yogurt manufacturers were capitalizing on its health food rep to help it gain widespread acceptance, with ads like Dannon's "Georgians Over 100" touting the supposed benefits of yogurt consumption. The 1980s saw its popularity increase further with the fad for frozen yogurt. More recently, the start up Chobani has helped spark a shift toward thicker, Greek-style yogurts which have largely replaced the thinner style.
[1]Holt, Jane. "News of Food; Yogurt, Milk Food Originating in Balkans, Is Gaining Wider Distribution in the City," New York Times, March 08, 1945.