Koreans don't get a third of their calories from dairy products, though. Whereas if Mongolians get ~30% of their calories from dairy on average (which is credible), that would mean they are getting far more than that in summer, since dairy consumption is largely seasonal. We're talking prodigious amounts by the standards of any culture, not a dash. That consumption includes both significant unfermented dairy (milk, milk tea, clotted cream) and dairy products fermented in a wide variety of ways.

Are lactose intolerance symptoms widespread among Mongolians? If not, and if Mongolians are really genetically lactose intolerant, then it is worth asking whether the fermented dairy foods (as opposed to kimchi) they consume are mitigating that intolerance.