The adoption agency Holt International, along with a number of service organizations including, Friends of Children of Viet Nam (FCVN), Friends For All Children (FFAC), Catholic Relief Service, International Social Services, International Orphans, and the Pearl S. Buck Foundation, petitioned the government to help evacuate the orphans residing in their facilities in South Vietnam.

So the US Military motivation was "yeah sounds good, we were already evacuating 50,000 people anyways".