Academic excellence implies good grades, and by the sound of it Hanyu and Zhou are the only ones who have grades to back up excellence claim.
in the States, the school system is so poor, that you can’t really judge on high school grades from home schooling.
And, well, the State’s bias towards athletics is proverbial.
What do the grades of students who are home-schooled--that is, whose parents have opted out of the school system--have to do with the standards of public or private schools?
As an American university professor who has studied and/or taught in three countries' higher-education system, I can say that there is a very wide range of qualification, preparation, and achievement in many countries, not only in the US. And differences in educational philosophies and aims make comparisons across systems difficult and less meaningful than one might think. For example, in the UK, students focusing on the humanities will most likely stop taking math or science courses after GCSE (age 16, with two years of pre-college schooling remaining), if not before. They will not be expected to take any math or science courses in university--or indeed, many if any courses outside their degree/major subject. In the US, students hoping to go to college will have to continue taking some math or science courses through high school, and will probably have to satisfy some breadth requirements to earn their college degrees. At my institution (a public flagship in the middle of the country), all students have to pass a calculus course to graduate, whether they're majoring in math or English. So who is more academically excellent: the student with a deep but narrow knowledge of one or a few interrelated subjects, or the student with a somewhat less comprehensive knowledge of one subject complemented by some knowledge of a broad range of subjects?
[In case it isn't clear, that's a rhetorical question; my point is that there are multiple valid ways of defining academic excellence.]