The persecution of religious minorities in Europe resulted in a very secular Europe—-because many of them fled—-and a very religious America, because that’s where they all went.
Only a small fraction of American settlers / colonists were fleeing religious persecution, and those mostly came from a few countries in western and northern Europe. There weren't many religious fanatics emigrating in the 1600's from Greece or Poland.
The enlightenment exploded after the Lisbon earthquake. Atheism took off. I don't think it was religious persecution as much as the emergence of secular philosophy and science.
No. The persecution of religious minorities in Europe culminated in the Holocaust, which led to the Universal Declaration of Human Rights. Don't blame the minorities who have suffered and continue to suffer.
Both/and, I think. If you don't like "them", and they're religiously different too, then religion becomes one more avenue for you to attack them. On the other hand, if it starts with you not liking their religion, then you can wind up not liking their ethnicity too.