Arg. is an immigrant base country but around 80% are from Spain and Italy.
So there are more hispanic people with black or brown hair than caucasian blond hair.
Is so rare that if you find one always is a legit german or exchange student.
Always this a misconception, JAPAN: Argentina is not Germany.
Actually, blonde hair is not as weird as you may think. White skin neither. Sure, it's not like living in a European Country, but there are enough of these people to not even even bat an eye when they appear.(A third of my classmates had European Ancestry). And that's in Salta, far north in Argentina, where the influence was lower. Buenos Aires is plagued with a lot of ethnic races as far as I know. Hell, I confused some Rioplatenses with European people at first glance.