Not all people are good; not all people are bad. It's a mix, and arguments pro and con tend to assume the extremes, good and bad. I think most people want to improve their lot. This is a way to help that aim for those who can. It's win-win for them and for the US. Some will abuse it, as my ull US-born nephew did when he worked hard to become an alcoholic while in the Marines. His behavior certainly didn't paint his comrades with the same tainted brush.