Research shows that immigrants tend to bring their prejudices with them, adopting the anti-immigrant sentiments of their new hosts. Middle-class immigrants may fear a loss of status. Others simply seek to distinguish themselves from a stigmatised group.
I suspect that it might be some form of hidden feeling of guilt.
people immigrate here, and feel guilty for intruding. then, they take up some form of anti-immigrant sentiment as a form of self-punishment?