Immigrants, sadly or not, depending on one's point of view, have historically been used to fill out the ranks of the American armed forces, since at least the Mexican War, so this doesn't come as a surprise to me. Considering the relatively low recruiting levels for the US Armed Forces in recent years, plus the lowering of physical, mental and psychological/moral standards for recruits in that same time frame, one can see where offering immigrant recruits citizenship would be "good business" from the Armed Forces' standpoint.
The Army has had such a programme going for the past few years now, and it's the descendant of rules and regulations found there, as well as in the US Navy, made in the 20th Century.
Immigrants are generally, like country boys in an earlier age, considered to be more ameanable to discipline, physically hardier and less likely to cause problems in ranks than American urbanites or suburban dwellers, who come from backgrounds that, for different reasons, potentially mean more time and trouble in keeping those soldiers in line.
It's exploitation, sure, just as the predominance of American poor and working-class boys and girls in the Armed Forces' ranks is yet another.
One could conceivably use this as an argument to return to some form of military conscription in the US, and it might work, up to a point.
The point beyond which it wouldn't work is that, like in the Viet-Nam War era, conscription would probably fall hardest on those of working-class and poor backgrounds who couldn't attend university or some other form of post-secondary studies, and who hadn't the necessary social and political connected parents, other relatives and family friends to get them exempted from military service.
Only a genuinely fair(if there's such a thing when it comes to military conscription)system, in which upper-class, upper-middle-class and lower-middle-class young people would go into the US Armed Forces as privates, the same as their working-class and poor counter-parts, and would serve out their time, just like everyone else.
The only exemptions that I can see granting under such a system would be to those who are their family's sole means of support, only children, physically or mentally disabled, or who have religious or ideological objections(i.e, Quakers, Baha'i and other sects known for their pacifist beliefs)to military service.
Academic studies and the like wouldn't be a means for exemption from military service under such a system.
But, such a system, I think, is unlikely to ever be imposed, or even if imposed, enforced in the manner which I described.
Someone would always find at least one loophole so that their Johnny, Jenny, etc, doesn't go into combat.
What the US might want to consider doing is getting itself out of the empire business for good and all, thus eliminating the necessity for luring immigrants and others into the ranks of the Armed Forces.
Until then, expect more of this sort of mis-deed, and my thoughts and hopes for the safe return of these boys and girls go out to them and their families.