[paulluuk]

I think their point is that you can not just say "children in china like math" or "children in france will drink wine", because those are stereotypes and there are many examples of children within those countries who do not conform.

They say that there are differences between even children living on two different roads in the same town, and these differences matter more than differences between countries, and therefore we should not make any kind of arguments based on nationality at all.

I disagree though, I do think that there are significant statistical differences growing up between, say, Afghanistan or Sweden. That does not mean that you can make claims about specific children in either country, but you can make generalizations about the population as a whole.