Uh, well, you see, when a Daddy Nazi and a Mommy Nazi get really scared of approaching Allied forces...

All of the Americas did. After the conservative clampdown of 1848, German nonconformists of many stripes emigrated to seek a better life in the new world. This included liberals (some of whom ended up bolstering the abolitionist cause in the US and Latin America) as well as unorthodox religious groups (most famous among them Amish, Mennonites and Anabaptists).

Not-so-fun fact: there was a large, creepily culty German religious separatist community in Chile for a long time. When Nazi war criminals looked for their boltholes, some of them ended up there. This did not improve things.

It's also worth noting that, at the time that first wave of Germans immigrated, Argentina was just as wealthy as the US and had all the same advantages re: natural resources etc. It's downright weird that it's failed to thrive ever since then.

Yeah, I think it is still demographically true that an Argentinian with a German last name is more likely to be a German Jew than a Nazi that came there through the Rat Lines. The reason Nazis went there in the first place is due to the large amount of German immigration previously, and the focus on Argentinian Nazis is part of the US deflection of how much Nazis the US took in for Operation Paperclip, Nazis doing medical experiments under Mengele, and SS members that started working for the CIA.