If by Europeans, you mean white, then that isn't true. The US incarcerates whites at the rate of 450 per 100k which is roughly double the rate of any European country except for Russia and equal to Russia's rate. It's triple or more the rate of incarceration in most of Western Europe.
If you are referring to people who are actually from European countries, then I haven't seen data on that, but Europeans in the US would be a very small non-representative sample of Europeans, so I fail to see the relevance.
Yes, Europe is sending us their best so the sample in the US is not representative.
I think you are responding to someone talking about people who share the cultural upbringing of Europe rather than race. Unless you think race is a powerful indicator of criminality?
If you are referring to people who are actually from European countries, then I haven't seen data on that, but Europeans in the US would be a very small non-representative sample of Europeans, so I fail to see the relevance.