Well, one interesting point is that native Mexicans and native Chinese would hardly recognize what we in the US call Mexican and Chinese.
As for Eastern European food, I think some of it may simply be quantity. I can't think of a single ethnic dish in my family that wasn't meant for an army and was meant for one. Even the article author talks about having made 1500 dumplings. And many of the dishes get better on the second day.
It also doesn't help that ethnic dishes tend to all have little quirks about how your mother, grandmother, etc. did it and you won't like somebody else's quirks. The author's grandmother had her own quirks to her dumplings, for example.