I think you're implicitly making an moral statement (putting aside whether its "correct"). Your focus on "costs to us and how much do we benefit" means we downplay or eliminate any consideration of the moral question. However, ignoring the moral question has the same effect as losing the moral argument to "this is our home and we shouldn't let strangers in" -- in both cases the moral argument for "joining us" is treated as irrelevant. I'm not making an argument, just an observation i think is relevant if considering the issue.
I don't see why this treats the moral argument for joining us as any less relevant than the moral argument for not joining us. And yes, this does downplay or eliminate consideration of the moral question, which is what I was going for. Or to put it another way, the moral statement I'm trying to make is that the moral value of absolutist moral considerations is less than utilitarian concerns in regards to costs/benefits. I don't actually care about moral arguments for or against immigration that aren't consequentalist.
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.