Claiming that christianity always and everywhere does this would be pretty obviously wrong, and I did not say this. And indeed even within europe today, catholic-ness is anti-correlated with this kind of "openness" -- because the core relevant for this has long since gone protestant or atheist.
I hold this claim weakly. There are other arguments for what happened. But regardless of why, my main point was that Europe (and especially a core area) was an outlier on this universalist/clannish scale. And that both ends have advantages, depending on the situation.
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.
And? The people running the catholic church around 1000 AD were not running the catholic church in Latin America in 1500 AD.
LOL
Oh please... Indian Catholic families still act in extended structures. I mean, three of my uncles are priests and one is a bishop. We've been Christian for thousands of years. We're still part of an overbearing, very close, very extended Indian family.
The ruining of European culture can be traced solely back to issues in European culture. Let's stop blaming the church for things that Europe brought upon itself.