So, what makes Argentina any different from, say, Mexico - except for the skin color of the average guy on the street, of course?
Its history? Of course - as has been said already - skin colour is a major part of that. It's basically another mid/late 19th century white settler colony, though less officially dependent on imperial powers than most at the time and less successful in the long run afterwards. Mexico is something else. Gross generalisation and oversimplification, granted.
Of course whether that makes it more or less 'Western' depends entirely on the definition of 'Western', doesn't it. Perhaps the problem here is the assumption of inferiority if somewhere is defined as being 'not Western' (whatever Western happens to mean).