The amount of "unaffiliated" Americans who move to Europe is probably negligible.
It would be one thing if people who are "unaffiliated USA citizens[0]" moved to an imaginary place where the grass is greener. You could argue they don't know about all the problems of that place.
It's maybe more concerning if the people who flew Place A, because of all the problems of Place A, looking for greener grass in Country B, are looking around and going "hey you know what? Place A wasn't so bad after all. The grass only looked greener because it's plastic!" and then go back.
[0]: let's acknowledge we're just talking shades of the same color, when referring to a country that's 250 years old. Nobody's "from there" really
At the time I moved to Ireland, I learned a vicious gang war was happening in the northern regions of Dublin. Up to April 2016, when I arrived, four (four!) people had been murdered in that unprecedented violent event.
I once had a Native American on one of my teams. That, and a lot of my fellow Brazilians here are at least partly of the original people.
Which came from Asia, through an ice bridge between Asia and North America a couple ice ages back, so, in the end, I guess we are all Africans.
I don't have any connection to Europe. I just don't want to live under America's increasing fascism and would rather contribute to a just society.