So some kid is born in the US to parents who are here as students, workers or whatever. His parents take him back home when they go. Why should he even care if he is legally a US citizen? Is this somehow special to a Panamanian, a German or a Thai?

If you feel that is an issue, get your senator or representative to cosponsor Nathan Deal's birthright citizenship bill. Of course, it has never gotten out of committee and it has zero chance of passage if it ever did.