It goes back further than WW2. Argentina obviously had a lot of European immigration, a lot of Italians, historically a lot of land was stolen from native and indigenous Argentinans and they were done away with. Even the biggest land owners there today are the Bennaton group, italians. There was a lot of racism towards native Argentinans.
Notice how you barely see any famous Argentinans that look native to South America? You would be forgiven for not even knowing such a group exists, they basically got pushed aside. Peruvians and Bolivians generally look very very native to their countries, and Argentinans as we see them today don't like that and treat them just like they did native Argentinans in the past, of which there aren't many left.
I think there's just historically a problem with racism/supremacy there and it's alive and well today.
Then it makes sense why they opened their arms to the nazis?
There's still actually small communities in Argentina where they speak German, its the offspring of Nazi's. Their communities even look German and you'll see nazi memorabilia.
As for Kun, he endorsed their new president, who many see as very right wing. Mind you, his opponent Massa was corrupt as hell, so I don't know if a lot of it was just to oppose him, as he was part of a lot of corruption in their former government. However, people were surprised to see Aguero publicly back Milei.
