It isn't as though they can't already subcontract out down there. As it is, there has to be a shell game - now the American firms who have interests down there have a better legal claim to their facilities. I don't see what the problem is with that.
Transnational corporations are no longer "American".
"Merchants have no country. The mere spot they stand on does not constitute so strong an attachment as that from which they draw their gains."
--Thomas Jefferson to Horatio G. Spafford, 1814. ME 14:119