But still this doesn't make sense, as Latin America was converted in the 1500s, well after the 1000 AD change that you claim occurred. Latin America, despite having 500 years for Catholicism to settle in, is still really big into the extended family.

I think a better explanation is the Protestant reformation weakened the idea that any person should subjugate their own personal individual desires for the greater good, with its emphasis on an individual quest for truth, an idea which has now permeated western culture. This makes sense with what I've experienced of non-European Catholicism, which mostly just finds Protestantism bizzare and confusing.