You're absolutely right that from a dietary perspective, and painting with a very broad brush, Chinese people in general eat healthier than Americans. My spouse certainly eats healthier than I do, though I've been a bit of a bad influence.
My point was about food safety, not nutrition. To some extent I can control how healthily my children eat by choosing what to feed them. But while in the US we can be fairly confident that the food and drugs they get are safe, that is less true in China, due in part to some recent food safety scandals like [0]. When we travel to China, there are certain things (like infant formula) that we bring with us rather than buy there. We also bring things like vitamins to my in-laws because they ask us to.