Here’s a link to the individual results of the 2017 Math Olympiad. The top 10 are from:
Iran
Japan
Vietnam
China
Republic of Georgia
USA (Chinese-American)
Belarus
Korea
Korea
Korea
The top Canadian (#15) also has a Chinese name.
The rest of the “Gold Medal” winners show a similar pattern of multi-national/multinational winners (except for Sub-Saharan Africa). But the facts never get in the way of snowflake race-mongers.