Will Wilkinson ponders immigrant attitudes towards immigration. He notes that "immigrants depress the wages of established immigrants and their children more than any other group, yet immigrants and their kids are (not really surprisingly) more enthusiastically pro-immigration than any other group":

Immigration massively increases the well-being of immigrants while hurting American natives very little, if at all. Yet most Americans don't consider it unfair to give the rights and welfare of foreigners little or no weight in deliberation over national immigration policy. So I think it's right to say that American immigration policy reflects a sense among Americans that considerations of group interest are morally legitimate when the group is the group of Americans. Yet members of families that have benefited from immigration viscerally grasp the harm and indignity of having one's own rights and welfare systematically discounted due to a contingency of birth.

This seems so wrong not so much because it hurts one's own in-group, but that it does so on the basis of the morally spurious in-group partiality of most Americans. It's unfair to so drastically discount the rights and welfare of those who fall outside the national in-group. It should come as no surprise that, in a national survey, those best placed to feel the sting of this unfairness should oppose it most strongly.