There was a long discussion about Jewish authors: the summary is that some, but not all, Jews are white. For more nuance on that, definitely check out the comments. Suggestions; more suggestions.

Most countries in the Americas, much like the U.S.A, are not racially homogenous. According to Wikipedia:

86.4% of Argentina's population self-identify as European descent. An estimated 8% of the population is mestizo. A further 4% of Argentines were of Arab or East Asian heritage. In the last national census, based on self-identification, 600,000 Argentines (1.6%) declared to be Amerindians.

You'd have to know the author's racial self-identity to be able to answer whether the author qualified for the comm.