Look, there is no doubt an equivalency in your method in that "they should join us" is put on the backburner along with "we should penalize them." I'm simply highlighting this point.

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.

In limiting the "consequentialist" argument to the "home country's" benefits and costs, you've by default given credence to the idea that "they should be penalized" in that you're willing to avoid penalizing them if they add value to your country -- another way of looking at it is to say those that want the immigrants to "join us" aren't benefited in any way by saying that the opposite moral argument was ignored. You've softened your statement now by using "moral value....is less," but you're actually going further than that -- you're saying that the utilitarian concerns on cost/benefits are SO GREAT relative to the moral issues that the moral issues should be ignored completely (or that's how your solution plays out). This is a bold statement, irrespective of its merits. How else would you interpret your statement?:

Immigration would be much better if we approached the issue of "How much do immigrants cost us vs how much do we benefit from them" and made laws in light of this, instead of approaching it from the moral difference between "This is our home and we shouldn't let strangers in" or "Freedom means allowing anyone to join us".

Your point only works if you completely ignore the moral argument. Once it matters even a little, the luxuries offered by cost/benefit analysis are thrown out the window because you now have a subjective consideration to incorporate that makes choices difficult. Again, just highlighting the consequences of your argument, don't really have an opinion on your particular argument.

Part of the problem with politics is we just say things and don't think about what they mean, since our focus is more on being right and presuming the potential certainty rather than understanding the sources and consequences of various political arguments and appreciating the inherent uncertainty that is unavoidable with any governance regime (or so I would argue).