[trhway]

>So who exactly is this helping?

it improves gene/social/economical makeup of American society first and foremost. Best and brightest young people is the best thing one can import.

Take just one very simple aspect - society needs infrastructure and resources committed for 20 years for 5 kids to get one successful college graduation bound educated young person. Out of the rest 4 some will during next 60 years of their life become a net negative like go to prison, unemployment, spawn next generation of low-productive members of society (cue in opening of "Idiocracy" :), etc... Or you can just "magically" import exactly that 1 bright and healthy 20 year old leaving the other 4 and the related 5 x 20 years expenditures to another country :)