It's true that people from Argentina generally are read as "Latino" when they come to the States, but most (or at least many) Argentines consider themselves to be white.
One of the many reasons racial politics can be far more complex than what often gets talked about.
For that last revival, Laurents also went on record as saying he wanted Sharks who were fluent in Spanish, and I think this linguistic difference is perhaps a better way to think about the difference in WSS.