..I am taking a risk in assuming that your idea of 'doing the right thing' arises a moral perspective rather than an economic one.
...Not that I am disagreeing with you, but morals differ greatly based upon the culture and the individual. I am quite sure that there are some very moral folks in both France, and now in San Bernardino, California who disagree that taking in Muslim immigrants is the 'right' thing to do.
..France's decision to accept these immigrants is laudable, but greatly influenced by the fact that they have the largest Muslim population in western Europe.
https://www.washingtonpost.com/news/worldviews/wp/2015/01/09/map-frances-growing-muslim-population/
...The argument of 'doing the right thing' falls flat when you are looking at an overburdened economic system on the verge of collapse. I teach students every day who are on free breakfast and lunch programs because their parents can't afford to feed them. I volunteer 2-3 times a month at a local church food kitchen feeding the 'economically challenged' and homeless. There just never seems to be enough resources to take care of everyone who needs help.
...Adding another 100,000 people to an already struggling economy makes little sense to me. Is it morally 'wrong' then to want scarce resources that would be spent in resettling and supporting immigrants to go to the feeding and care of people already struggling to survive in the U.S.? Should the care of previous waves of immigration (Iraqi, Somalian, Nigerian etc..) suffer for the care of a newer one?
...Please don't think that I am trying to be belligerent. There just doesn't seem to be any really good answers or solutions. Dealing with poverty and suffering is overwhelming. Regardless of how hard it is fought, it never seems to end.