Focusing on your last paragraph, I can't imagine reasonable people disagreeing with it.  That we have a duty as Christians to love not only our own people but those of other countries is not debatable --- not to a Christian.  But loving the poor of other countries doesn't require us to take them in, not if it harms us or  is not in our best interest.  While we have a duty to help the poor, we have no duty to turn ourselves into a third-world country.