"Is this a colonial phenomenon, perhaps?"

I would agree, Blu. My guess, which might be way off, is that amalgamated european americans are trying to find their own past and identity. When people ask me where I'm from, they often don't accept my answering "United States", even though my family has been here for many, many generations (Some came on the Mayflower too). I think out of guilt because of poor race relations here, we've told ourselves that we can't be "proud" of our ancestors or history, but recently I think many of us are realizing that we, just like any other person, CAN have a healthy pride about our past without wishing anyone else any ill will. Maybe in the "old countries" they already feel more connected to their history, and so don't feel so strong of a pull to find their identity this way.