I think it's because they see the American workforce is rapidly declining, and rather than taking the Paul Ryan route of asking American women to go bareback, they come to the logical conclusion that it'd be in America's best interest to give permanent employment rights to human labor which is already readily available in this country. You know, rather than taking 800,000 people out of the work force and then complaining that the workforce can't keep up with labor demand and American women need to have more babies.

EDIT: Sorry, meant to reply this to the person who asked why the Koch brothers are fighting so hard for us -- I'm high, my bad.