Why do programs sponsor candidates who won't stay in America after residency?

Real question. I am a US citizen IMG who struggled to match. After a few years of trying, I have decided to move on with my life. I know non-US IMGs who matched matched into US residency programs and went back to their country to practice medicine. Is there a reason why I worked, paid state and federal taxes, my parents work and pay taxes...and someone who won't even stay in this country after residency, gets paid by Medicare to be a resident? So the fact that I would have worked my tail... Why do programs sponsor candidates who won't stay in America after residency?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums