I do not doubt that for a moment. I just don't see why that is not a cultural cause; being persecuted by one culture and seeking refuge in another, by my view.I know why they emigrated, it was persecution that motivated them, and how they lived. They did not seek to impose their culture nor did they seek to adopt American culture uncritically. They were classic "hyphenated" Americans just as is true for many others.
More significantly for this thread's purposes, it also seems to me that it is unavoidable (and very often constructive) to bring a bit of one's culture of origin when one adopts another.
Mind you, it may be helpful to remind you that I am a Brazilian, and a particularly unattached one at that. I am not one to insist on the merits of keeping true to one's original culture. That just doesn't make a lot of sense to me.