The way you framed the discussion could come off as accusatory.
In a book by Cortázar where he was paraphrasing someone else, he said something like, "Mexicans came from Aztecs, Peruvians came from Incas, but the Argentines came from boats." So, in other words, Argentina, and the Cono Sur in general, had much more direct immigration from Europe in the 20th century (much like the US) which makes it a bit of a cultural outlier in Latin America.
This is changing. There is a huge population from other parts of Latin America. They are not of European descent. I have seen a massive change in the population of Buenos Aires over the years. There is even an African population now. I don't believe Porteños can any longer describe themselves as European in the early to mid 20th century of the term. Large parts of Europe are now multi racial, multi ethnic. The 'very European' description of BA is becoming antiquated. Pockets of BA remain that way - get out of those pockets and you will see the reality.